• "Sampler??"

    From Cursitor Doom@21:1/5 to All on Sun Jul 28 17:31:52 2024
    Gentlemen,

    I'm in the process of trying to track down a fault in my main HP spectrum analyzer. I've narrowed the issue down to the area of this "sampler" which
    is part of a phase locked loop. I'm not sure I fully understand its
    function, however. In particular, I'm extremely confused as to why they're calling it a "sampler" because when that term arises, I typically think of something doing akin to what a sampling oscilloscope does: noting voltage levels at predetermined intervals. AFAICS, this "sampler" is doing no such thing. It's just a harmonic mixer, surely? If not, I must be nuts. YOU get
    to decide!

    Block diagram here: https://disk.yandex.com/i/YXcGssgDXwVEbg

    Short functional description here:
    https://disk.yandex.com/i/k7YTYTGjHltsGw

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to cd999666@notformail.com on Sun Jul 28 10:41:26 2024
    On Sun, 28 Jul 2024 17:31:52 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    Gentlemen,

    I'm in the process of trying to track down a fault in my main HP spectrum >analyzer. I've narrowed the issue down to the area of this "sampler" which
    is part of a phase locked loop. I'm not sure I fully understand its
    function, however. In particular, I'm extremely confused as to why they're >calling it a "sampler" because when that term arises, I typically think of >something doing akin to what a sampling oscilloscope does: noting voltage >levels at predetermined intervals. AFAICS, this "sampler" is doing no such >thing. It's just a harmonic mixer, surely? If not, I must be nuts. YOU get
    to decide!

    Block diagram here: https://disk.yandex.com/i/YXcGssgDXwVEbg

    Short functional description here:
    https://disk.yandex.com/i/k7YTYTGjHltsGw

    From the description, it sounds just like the circuit of a sampling oscilloscope. An SRD impulse generator and some diodes, probably.

    Post the schematic of the sampler circuit.

    A sampler IS a harmonic mixer.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Sun Jul 28 17:59:41 2024
    On Sun, 28 Jul 2024 10:41:26 -0700, john larkin wrote:

    On Sun, 28 Jul 2024 17:31:52 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    Gentlemen,

    I'm in the process of trying to track down a fault in my main HP
    spectrum analyzer. I've narrowed the issue down to the area of this >>"sampler" which is part of a phase locked loop. I'm not sure I fully >>understand its function, however. In particular, I'm extremely confused
    as to why they're calling it a "sampler" because when that term arises,
    I typically think of something doing akin to what a sampling
    oscilloscope does: noting voltage levels at predetermined intervals. >>AFAICS, this "sampler" is doing no such thing. It's just a harmonic
    mixer, surely? If not, I must be nuts. YOU get to decide!


    Short functional description here:
    https://disk.yandex.com/i/k7YTYTGjHltsGw

    From the description, it sounds just like the circuit of a sampling oscilloscope. An SRD impulse generator and some diodes, probably.

    Post the schematic of the sampler circuit.

    A sampler IS a harmonic mixer.

    This - see link - is about as much detail as they provide. Seems the
    "sampler" is perhaps proprietory and they don't want it copied I would
    guess.

    https://disk.yandex.com/i/0p1smcx2qgV1Qg

    I don't know how you equate a sampler to a harmonic mixer; I don't see any similarity at all.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ehsjr@21:1/5 to Cursitor Doom on Sun Jul 28 16:15:06 2024
    On 7/28/2024 1:31 PM, Cursitor Doom wrote:
    Gentlemen,

    I'm in the process of trying to track down a fault in my main HP spectrum analyzer. I've narrowed the issue down to the area of this "sampler" which
    is part of a phase locked loop. I'm not sure I fully understand its
    function, however. In particular, I'm extremely confused as to why they're calling it a "sampler" because when that term arises, I typically think of something doing akin to what a sampling oscilloscope does: noting voltage levels at predetermined intervals. AFAICS, this "sampler" is doing no such thing. It's just a harmonic mixer, surely? If not, I must be nuts. YOU get
    to decide!

    Block diagram here: https://disk.yandex.com/i/YXcGssgDXwVEbg

    Short functional description here:
    https://disk.yandex.com/i/k7YTYTGjHltsGw

    Too bad they don't call it a "frequency sampler".
    In essence (perhaps over simplified) that's
    what it does. It produces the frequencies above
    and below the center frequency (the spectrum) to
    be portrayed on the screen. As you noted, it does
    that by harmonic mixing. You might want to think
    about it with a change in your statement about an
    oscilloscope:
    From "noting voltage levels at predetermined intervals."
    to "noting voltage levels at predetermined frequencies."

    Maybe that helps.
    Ed

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to ehsjr on Sun Jul 28 20:28:25 2024
    ehsjr <ehsjr@verizon.net> wrote:
    On 7/28/2024 1:31 PM, Cursitor Doom wrote:
    Gentlemen,

    I'm in the process of trying to track down a fault in my main HP spectrum
    analyzer. I've narrowed the issue down to the area of this "sampler" which >> is part of a phase locked loop. I'm not sure I fully understand its
    function, however. In particular, I'm extremely confused as to why they're >> calling it a "sampler" because when that term arises, I typically think of >> something doing akin to what a sampling oscilloscope does: noting voltage
    levels at predetermined intervals. AFAICS, this "sampler" is doing no such >> thing. It's just a harmonic mixer, surely? If not, I must be nuts. YOU get >> to decide!

    Block diagram here: https://disk.yandex.com/i/YXcGssgDXwVEbg

    Short functional description here:
    https://disk.yandex.com/i/k7YTYTGjHltsGw

    Too bad they don't call it a "frequency sampler".
    In essence (perhaps over simplified) that's
    what it does. It produces the frequencies above
    and below the center frequency (the spectrum) to
    be portrayed on the screen. As you noted, it does
    that by harmonic mixing. You might want to think
    about it with a change in your statement about an
    oscilloscope:
    From "noting voltage levels at predetermined intervals."
    to "noting voltage levels at predetermined frequencies."

    Maybe that helps.
    Ed


    It’s good that they don’t call it that, because that’s not what it does. Stroboscopic sampling is familiar from old Westerns, where the spoked
    wheels of wagons seemed to turn backwards in certain speed ranges.

    (I haven’t watched a movie for a looong while, but I expect that that
    effect gets removed in post these days. )

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to Cursitor Doom on Mon Jul 29 00:06:20 2024
    On 7/28/24 23:40, Cursitor Doom wrote:

    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. The signal from the LHS is passed through a very fast diode which generates harmonics from that fundamental. The signal from the RHS is unmodified and mixed with the desired harmonic to give the necessary output signal which
    is then filtered to get rid of the unwanted mixing products. If that's all correct, as I believe it is, where does any *sampling* come into it?

    With some simplification, one could say a mixer alternately
    multiplies its input signal by +1 or -1, whereas a sampler
    multiplies its input by 0 or 1. The functions are very similar.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
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  • From john larkin @21:1/5 to cd999666@notformail.com on Sun Jul 28 14:42:42 2024
    On Sun, 28 Jul 2024 17:59:41 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Sun, 28 Jul 2024 10:41:26 -0700, john larkin wrote:

    On Sun, 28 Jul 2024 17:31:52 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    Gentlemen,

    I'm in the process of trying to track down a fault in my main HP
    spectrum analyzer. I've narrowed the issue down to the area of this >>>"sampler" which is part of a phase locked loop. I'm not sure I fully >>>understand its function, however. In particular, I'm extremely confused >>>as to why they're calling it a "sampler" because when that term arises,
    I typically think of something doing akin to what a sampling
    oscilloscope does: noting voltage levels at predetermined intervals. >>>AFAICS, this "sampler" is doing no such thing. It's just a harmonic >>>mixer, surely? If not, I must be nuts. YOU get to decide!


    Short functional description here: >>>https://disk.yandex.com/i/k7YTYTGjHltsGw

    From the description, it sounds just like the circuit of a sampling
    oscilloscope. An SRD impulse generator and some diodes, probably.

    Post the schematic of the sampler circuit.

    A sampler IS a harmonic mixer.

    This - see link - is about as much detail as they provide. Seems the >"sampler" is perhaps proprietory and they don't want it copied I would
    guess.

    https://disk.yandex.com/i/0p1smcx2qgV1Qg

    I don't know how you equate a sampler to a harmonic mixer; I don't see any >similarity at all.

    The only difference is whether you think about it in the frequency
    domain or in the time domain. The circuit doesn't care.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Phil Hobbs on Sun Jul 28 23:04:45 2024
    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked
    wheels of wagons seemed to turn backwards in certain speed ranges.

    I can get my head around that kind of sampling no problem. But there's
    nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a
    mixer. Come to think of it, I don't really know anything about them other
    than you input two different frequency signals which intermodulate and you
    get the sum and the difference of them at the output; then filter for the
    one you need. Is this intermodulation some form of sampling?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Cursitor Doom on Sun Jul 28 21:16:56 2024
    On 2024-07-28 19:04, Cursitor Doom wrote:
    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked
    wheels of wagons seemed to turn backwards in certain speed ranges.

    I can get my head around that kind of sampling no problem. But there's nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a
    mixer. Come to think of it, I don't really know anything about them other than you input two different frequency signals which intermodulate
    and you
    get the sum and the difference of them at the output; then filter for the one you need. Is this intermodulation some form of sampling?


    More or less, sometimes a lot more. Here goes.

    **FREQUENCY MIXING**
    In signal processing theory, we often model a mixer as multiplying the
    RF input signal by a sinusoidal local oscillator (LO) to produce the intermediate frequency (IF) output. ['IF' isn't a great name, because
    it sounds like there's only one frequency there. In fact there are
    nearly always lots of components at different frequencies, which we have
    to separate with filters.]

    That’s mathematically pretty simple, requiring only the formulas for
    products of sines and cosines. Those are simple to derive from the
    definitions if you forget which way the signs go. For reference,

    cos(a+b) = cos a cos b - sin a sin b (1)
    cos(a-b) = cos a cos b + sin a sin b (2)

    so

    sin a sin b = 0.5 * [ cos(a-b) - cos(a+b) ] (3) and
    cos a cos b = 0.5 * [ cos(a-b) + cos(a+b) ] (4)

    the sin * cos versions come from the formula for sin(a+b), and are left
    as an exercise for the reader. ;) (In real life, you can put the phase
    shifts into the arguments rather than using different formulas.)

    Mixers like this are said to be *bilinear*, because they're linear in
    both inputs--if you multiply 2x * y, or x * 2y, you get 2xy.

    The net is that you get two copies of your signal, one upshifted by the
    LO frequency and the other downshifted. (There’s an absolute value in
    the downshifted frequency, because it’s convenient to deal with positive frequencies.)(*)

    **SWITCHING MIXERS**
    Most real mixers are a bit different, because linear mixing is hard to
    do well. A radio has to deal with whatever comes in from the antenna,
    which may well include other signals that are much stronger than the one
    you want, and a bad mixer will cause all sorts of problems when that
    happens. (Search for 'cross modulation' for one example. Ignore the AI results.)

    Thus most mixers are switching types, which are effectively multipliers
    where the LO is a fixed-amplitude square wave rather than a
    variable-amplitude sine. You can verify with your favorite math program
    that a square wave

    SQ(t) = 1 0< t < pi
    = -1 pi < t < 2*pi (and so on) (5)

    is given by

    SQ(t) = sin(t) + sin(3 t)/3 + sin(5 t)/ 5 +.... , (6)

    i.e. the sum of all the odd harmonics, with an amplitude falloff on the higher-order terms.

    Thus when you multiply your RF signal A*sin(omega1 t) by the LO signal
    SQ(omega t), you get

    IF = sin( omegaR t) * [ sin( omegaL t) + sin( 3*omegaL t)/3 + ....), (7)

    which using (3) is

    2*IF = cos[(omegaR-omegaL) * t] + cos[(omegaR-3*omegaL) * t]/3 + ...
    - cos[(omegaR+omegaL) * t] - cos[(omegaR+3*omegaL) * t]/3 - .... (8)

    The top line of (8) is the lower sideband (LSB) contributions, and the
    bottom line is the upper sideband (USB) ones. We get contributions of
    all orders (2N+1), where N is any integer. (Eventually the LSB
    frequencies cross 0 Hz and start back up again, which takes a bit more
    thought if we care about stuff that far out.)

    The amplitudes of these components fall off like 1/(2N+1), which is not
    very fast--the far-out 15*omegaL terms are down by only 24 dB compared
    to the 1*omegaL terms. Thus we usually need to filter out the
    higher-order terms. (**) This added complexity is usually worth it,
    because switching mixers are much stronger (i.e. resistant to intermod
    and other spurious products) than proper multipliers. They also tend to
    be cheaper, and work over a much wider frequency range.

    **SAMPLING**
    The positive part of a square wave has the same width as the negative
    part. If we notionally make the positive part narrower and narrower,
    and taller and taller to keep the area the same (***), we arrive at the sampling mixer.

    The usual mathematical notation for the sampling function is sha(x),
    after the Cyrillic letter that looks like III smushed together into one character. For now, we note that the positive peaks of sin(omegaL*t)
    are also peaks (positive or negative) of sin[ (2N+1) * omegaL * t].
    Thus all the odd-order harmonics of omegaL come in at the same strength,
    and don't fall off like 1/(2N+1) as in the square wave case.

    That means that with suitable filtering, we can use the sampling mixer
    to effectively mix omegaR with omegaL * (2N+1), i.e. as a harmonic
    mixer. That's often very useful in instruments.

    If we lowpass filter the IF, so that we just get the baseband
    component, we can use the sampling mixer as a phase detector in a PLL,
    still at any N we like.

    And of course we can just use it to take stroboscopic samples of a
    repetitive waveform, as in a sampling scope.

    Cheers

    Phil Hobbs
    (Who occasionally gets the urge to actually explain something)

    (*) Every once in awhile we get into an argument round here, because
    some folks think that there's no way to get different frequencies in the
    output without nonlinearity. That's true for a single input port, but
    not when you have two, as we see by construction.

    (**) For an actual radio, there will be a lot of other signals on the RF
    port, which will lead to an absolute forest of spurious products if you
    don't choose the IF frequency correctly, and choose the correct
    sideband. A good *frequency plan* will give a nice clean RX signal
    using not-too-horrible filters, but it sure doesn't happen by accident.

    (***) With the negative part's amplitude reduced to keep the DC response
    zero, of course.

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Phil Hobbs on Sun Jul 28 21:21:02 2024
    On 2024-07-28 21:16, Phil Hobbs wrote:
    On 2024-07-28 19:04, Cursitor Doom wrote:
    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked
    wheels of wagons seemed to turn backwards in certain speed ranges.

    I can get my head around that kind of sampling no problem. But there's nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a mixer. Come to think of it, I don't really know anything about them
    other
    than you input two different frequency signals which intermodulate
    and you
    get the sum and the difference of them at the output; then filter for
    the
    one you need. Is this intermodulation some form of sampling?


    More or less, sometimes a lot more.  Here goes.

    **FREQUENCY MIXING**
    In signal processing theory, we often model a mixer as multiplying the
    RF input signal by a sinusoidal local oscillator (LO) to produce the intermediate frequency (IF) output.  ['IF' isn't a great name, because
    it sounds like there's only one frequency there.  In fact there are
    nearly always lots of components at different frequencies, which we have
    to separate with filters.]

    That’s mathematically pretty simple, requiring only the formulas for products of sines and cosines. Those are simple to derive from the definitions if you forget which way the signs go. For reference,

    cos(a+b) = cos a cos b - sin a sin b  (1)
    cos(a-b) = cos a cos b + sin a sin b  (2)

    so

    sin a sin b = 0.5 * [ cos(a-b) - cos(a+b) ]  (3) and
    cos a cos b = 0.5 * [ cos(a-b) + cos(a+b) ]  (4)

    the sin * cos versions come from the formula for sin(a+b), and are left
    as an exercise for the reader. ;)  (In real life, you can put the phase shifts into the arguments rather than using different formulas.)

    Mixers like this are said to be *bilinear*, because they're linear in
    both inputs--if you multiply 2x * y, or x * 2y, you get 2xy.

    The net is that you get two copies of your signal, one upshifted by the
    LO frequency and the other downshifted. (There’s an absolute value in
    the downshifted frequency, because it’s convenient to deal with positive frequencies.)(*)

    **SWITCHING MIXERS**
    Most real mixers are a bit different, because linear mixing is hard to
    do well.  A radio has to deal with whatever comes in from the antenna,
    which may well include other signals that are much stronger than the one
    you want, and a bad mixer will cause all sorts of problems when that happens.  (Search for 'cross modulation' for one example. Ignore the AI results.)

    Thus most mixers are switching types, which are effectively multipliers
    where the LO is a fixed-amplitude square wave rather than a variable-amplitude sine.  You can verify with your favorite math program that a square wave

    SQ(t) = 1   0< t < pi
          = -1  pi < t < 2*pi (and so on)  (5)

    is given by

    SQ(t) = sin(t) + sin(3 t)/3 + sin(5 t)/ 5 +.... , (6)

    (There's actually a factor of 4/pi in front of all that, which I forgot
    about. Otherwise OK.)

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to cd999666@notformail.com on Sun Jul 28 19:16:10 2024
    On Sun, 28 Jul 2024 21:40:41 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. The >signal from the LHS is passed through a very fast diode which generates >harmonics from that fundamental. The signal from the RHS is unmodified and >mixed with the desired harmonic to give the necessary output signal which
    is then filtered to get rid of the unwanted mixing products. If that's all >correct, as I believe it is, where does any *sampling* come into it?

    Mixing = sampling = multiplication.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to Doom on Mon Jul 29 05:19:06 2024
    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened Cursitor Doom <cd999666@notformail.com> wrote in <v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. The >signal from the LHS is passed through a very fast diode which generates >harmonics from that fundamental. The signal from the RHS is unmodified and >mixed with the desired harmonic to give the necessary output signal which
    is then filtered to get rid of the unwanted mixing products. If that's all >correct, as I believe it is, where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to Doom on Mon Jul 29 05:24:31 2024
    On a sunny day (Sun, 28 Jul 2024 23:04:45 -0000 (UTC)) it happened Cursitor Doom <cd999666@notformail.com> wrote in <v86iqd$3n74$2@dont-email.me>:

    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked
    wheels of wagons seemed to turn backwards in certain speed ranges.

    I can get my head around that kind of sampling no problem. But there's >nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a
    mixer. Come to think of it, I don't really know anything about them other >than you input two different frequency signals which intermodulate and you >get the sum and the difference of them at the output; then filter for the
    one you need. Is this intermodulation some form of sampling?

    Consider a simple PLL with a sampling gate as phase discriminator.
    When the frequencies are equal the output is some DC value, its amplitude depending on the phase difference.

    When one frequency goes a bit up, the output is the difference frequency. etc...

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to All on Sun Jul 28 21:40:41 2024
    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. The
    signal from the LHS is passed through a very fast diode which generates harmonics from that fundamental. The signal from the RHS is unmodified and mixed with the desired harmonic to give the necessary output signal which
    is then filtered to get rid of the unwanted mixing products. If that's all correct, as I believe it is, where does any *sampling* come into it?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to All on Mon Jul 29 10:05:56 2024
    On Sun, 28 Jul 2024 19:16:10 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 28 Jul 2024 21:40:41 -0000 (UTC), Cursitor Doom ><cd999666@notformail.com> wrote:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. The >>signal from the LHS is passed through a very fast diode which generates >>harmonics from that fundamental. The signal from the RHS is unmodified and >>mixed with the desired harmonic to give the necessary output signal which >>is then filtered to get rid of the unwanted mixing products. If that's all >>correct, as I believe it is, where does any *sampling* come into it?

    Mixing = sampling = multiplication.

    Apples = oranges = pears is an equally valid statement!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Mon Jul 29 10:03:02 2024
    On Sun, 28 Jul 2024 21:21:02 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    On 2024-07-28 21:16, Phil Hobbs wrote:
    On 2024-07-28 19:04, Cursitor Doom wrote:
    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked
    wheels of wagons seemed to turn backwards in certain speed ranges.

    I can get my head around that kind of sampling no problem. But there's
    nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a
    mixer. Come to think of it, I don't really know anything about them
    other
    than you input two different frequency signals which intermodulate
    and you
    get the sum and the difference of them at the output; then filter for
    the
    one you need. Is this intermodulation some form of sampling?


    More or less, sometimes a lot more.  Here goes.

    **FREQUENCY MIXING**
    In signal processing theory, we often model a mixer as multiplying the
    RF input signal by a sinusoidal local oscillator (LO) to produce the
    intermediate frequency (IF) output.  ['IF' isn't a great name, because
    it sounds like there's only one frequency there.  In fact there are
    nearly always lots of components at different frequencies, which we have
    to separate with filters.]

    That’s mathematically pretty simple, requiring only the formulas for
    products of sines and cosines. Those are simple to derive from the
    definitions if you forget which way the signs go. For reference,

    cos(a+b) = cos a cos b - sin a sin b  (1)
    cos(a-b) = cos a cos b + sin a sin b  (2)

    so

    sin a sin b = 0.5 * [ cos(a-b) - cos(a+b) ]  (3) and
    cos a cos b = 0.5 * [ cos(a-b) + cos(a+b) ]  (4)

    the sin * cos versions come from the formula for sin(a+b), and are left
    as an exercise for the reader. ;)  (In real life, you can put the phase
    shifts into the arguments rather than using different formulas.)

    Mixers like this are said to be *bilinear*, because they're linear in
    both inputs--if you multiply 2x * y, or x * 2y, you get 2xy.

    The net is that you get two copies of your signal, one upshifted by the
    LO frequency and the other downshifted. (There’s an absolute value in
    the downshifted frequency, because it’s convenient to deal with positive
    frequencies.)(*)

    **SWITCHING MIXERS**
    Most real mixers are a bit different, because linear mixing is hard to
    do well.  A radio has to deal with whatever comes in from the antenna,
    which may well include other signals that are much stronger than the one
    you want, and a bad mixer will cause all sorts of problems when that
    happens.  (Search for 'cross modulation' for one example. Ignore the AI
    results.)

    Thus most mixers are switching types, which are effectively multipliers
    where the LO is a fixed-amplitude square wave rather than a
    variable-amplitude sine.  You can verify with your favorite math program
    that a square wave

    SQ(t) = 1   0< t < pi
          = -1  pi < t < 2*pi (and so on)  (5)

    is given by

    SQ(t) = sin(t) + sin(3 t)/3 + sin(5 t)/ 5 +.... , (6)

    (There's actually a factor of 4/pi in front of all that, which I forgot >about. Otherwise OK.)

    Cheers

    Phil Hobbs

    Many thanks indeed for that *fully comprehensive* explanation, Phil.
    At times like this when I have to grasp something of this nature I
    find strong coffee and donuts help enormously. I'm about to place a
    special order I suspect....

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to All on Mon Jul 29 12:06:31 2024
    On Mon, 29 Jul 2024 05:24:31 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Sun, 28 Jul 2024 23:04:45 -0000 (UTC)) it happened Cursitor >Doom <cd999666@notformail.com> wrote in <v86iqd$3n74$2@dont-email.me>:

    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked
    wheels of wagons seemed to turn backwards in certain speed ranges.

    I can get my head around that kind of sampling no problem. But there's >>nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a >>mixer. Come to think of it, I don't really know anything about them other >>than you input two different frequency signals which intermodulate and you >>get the sum and the difference of them at the output; then filter for the >>one you need. Is this intermodulation some form of sampling?

    Consider a simple PLL with a sampling gate as phase discriminator.
    When the frequencies are equal the output is some DC value, its amplitude depending on the phase difference.

    When one frequency goes a bit up, the output is the difference frequency. >etc...

    I don't see the relevance here. If by 'sampling gate' you mean 'sample
    & hold' - which I assume you do - that's a different part of the loop altogether from the part labled 'sampler' in the block diagram.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to cd@notformail.com on Mon Jul 29 11:30:08 2024
    On a sunny day (Mon, 29 Jul 2024 12:06:31 +0100) it happened Cursitor Doom <cd@notformail.com> wrote in <7qteaj94r7l8n9ct4h16kviugq6shkp384@4ax.com>:

    On Mon, 29 Jul 2024 05:24:31 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Sun, 28 Jul 2024 23:04:45 -0000 (UTC)) it happened Cursitor >>Doom <cd999666@notformail.com> wrote in <v86iqd$3n74$2@dont-email.me>:

    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked
    wheels of wagons seemed to turn backwards in certain speed ranges.

    I can get my head around that kind of sampling no problem. But there's >>>nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a >>>mixer. Come to think of it, I don't really know anything about them other >>>than you input two different frequency signals which intermodulate and you >>>get the sum and the difference of them at the output; then filter for the >>>one you need. Is this intermodulation some form of sampling?

    Consider a simple PLL with a sampling gate as phase discriminator.
    When the frequencies are equal the output is some DC value, its amplitude depending on the phase difference.

    When one frequency goes a bit up, the output is the difference frequency. >>etc...

    I don't see the relevance here. If by 'sampling gate' you mean 'sample
    & hold' - which I assume you do - that's a different part of the loop >altogether from the part labled 'sampler' in the block diagram.

    Idujno,Ifind that diagram very much crap, more a block diagram

    I wonder, did you EVER design any electronics?
    Try building a sampling circuit, or that instrument you are carrying on about to get a feel for what counts, so you CAN do fast fault finding.
    Else endless blur makes you see nothing.
    Should take 10 minutes to fix the thing if you did not damage it before hand.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to All on Mon Jul 29 12:50:33 2024
    On Mon, 29 Jul 2024 11:30:08 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Mon, 29 Jul 2024 12:06:31 +0100) it happened Cursitor Doom ><cd@notformail.com> wrote in <7qteaj94r7l8n9ct4h16kviugq6shkp384@4ax.com>:

    On Mon, 29 Jul 2024 05:24:31 GMT, Jan Panteltje <alien@comet.invalid> >>wrote:

    On a sunny day (Sun, 28 Jul 2024 23:04:45 -0000 (UTC)) it happened Cursitor >>>Doom <cd999666@notformail.com> wrote in <v86iqd$3n74$2@dont-email.me>:

    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked >>>>> wheels of wagons seemed to turn backwards in certain speed ranges.

    I can get my head around that kind of sampling no problem. But there's >>>>nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a >>>>mixer. Come to think of it, I don't really know anything about them other >>>>than you input two different frequency signals which intermodulate and you >>>>get the sum and the difference of them at the output; then filter for the >>>>one you need. Is this intermodulation some form of sampling?

    Consider a simple PLL with a sampling gate as phase discriminator.
    When the frequencies are equal the output is some DC value, its amplitude depending on the phase difference.

    When one frequency goes a bit up, the output is the difference frequency. >>>etc...

    I don't see the relevance here. If by 'sampling gate' you mean 'sample
    & hold' - which I assume you do - that's a different part of the loop >>altogether from the part labled 'sampler' in the block diagram.

    Idujno,Ifind that diagram very much crap, more a block diagram

    Yes, it's a block diagram which shows the device labeled as a
    "sampler" comes before the phase detector, after which comes the
    sample and hold part.

    I wonder, did you EVER design any electronics?

    No. And I've never made any secret of that here.

    Try building a sampling circuit, or that instrument you are carrying on about >to get a feel for what counts, so you CAN do fast fault finding.
    Else endless blur makes you see nothing.
    Should take 10 minutes to fix the thing if you did not damage it before hand.

    I can't fix it if I don't fully understand what it does, hence the
    original question.
    Anyway, it's clear that regardless of what HP call the thing, it's
    just a harmonic mixer and if I proceed on that basis, I should be able
    to trace the issue.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to Cursitor Doom on Mon Jul 29 23:52:45 2024
    On 29/07/2024 7:05 pm, Cursitor Doom wrote:
    On Sun, 28 Jul 2024 19:16:10 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 28 Jul 2024 21:40:41 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. The
    signal from the LHS is passed through a very fast diode which generates
    harmonics from that fundamental. The signal from the RHS is unmodified and >>> mixed with the desired harmonic to give the necessary output signal which >>> is then filtered to get rid of the unwanted mixing products. If that's all >>> correct, as I believe it is, where does any *sampling* come into it?

    Mixing = sampling = multiplication.

    Apples = oranges = pears is an equally valid statement!

    It may look that way to you, but all that that signifies is that you
    haven't studied the subject, and have yet to work out that you need to.

    Phil Hobbs has spelled it all out in some detail, but that all seems to
    have gone way over your head.

    John Larkin has got it more or less right, but his presentation is a
    trifle over-simplified, if still not down to your level.

    --
    Bill Sloman, Sydney


    --
    This email has been checked for viruses by Norton antivirus software. www.norton.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Mon Jul 29 09:03:08 2024
    On Mon, 29 Jul 2024 12:06:31 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Mon, 29 Jul 2024 05:24:31 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Sun, 28 Jul 2024 23:04:45 -0000 (UTC)) it happened Cursitor >>Doom <cd999666@notformail.com> wrote in <v86iqd$3n74$2@dont-email.me>:

    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked
    wheels of wagons seemed to turn backwards in certain speed ranges.

    I can get my head around that kind of sampling no problem. But there's >>>nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a >>>mixer. Come to think of it, I don't really know anything about them other >>>than you input two different frequency signals which intermodulate and you >>>get the sum and the difference of them at the output; then filter for the >>>one you need. Is this intermodulation some form of sampling?

    Consider a simple PLL with a sampling gate as phase discriminator.
    When the frequencies are equal the output is some DC value, its amplitude depending on the phase difference.

    When one frequency goes a bit up, the output is the difference frequency. >>etc...

    I don't see the relevance here. If by 'sampling gate' you mean 'sample
    & hold' - which I assume you do - that's a different part of the loop >altogether from the part labled 'sampler' in the block diagram.

    Technically, a sampler works in the Nyquist/Shannon sense, namely
    multiplies a signal by a unit impulse. A sample-and-hold is a bit
    different, because its output is a boxcar waveform, not a series of
    impulses. The frequency response is different.

    The sampler in you spectrum analyzer block diagram is what it says, a
    sampler. HP wouldn't lie about that.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to cd@notformail.com on Mon Jul 29 15:56:22 2024
    On a sunny day (Mon, 29 Jul 2024 12:50:33 +0100) it happened Cursitor Doom <cd@notformail.com> wrote in <p80fajltc50rajhib7dqjn6mbni6d8ko6q@4ax.com>:

    On Mon, 29 Jul 2024 11:30:08 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Mon, 29 Jul 2024 12:06:31 +0100) it happened Cursitor Doom >><cd@notformail.com> wrote in <7qteaj94r7l8n9ct4h16kviugq6shkp384@4ax.com>:

    On Mon, 29 Jul 2024 05:24:31 GMT, Jan Panteltje <alien@comet.invalid> >>>wrote:

    On a sunny day (Sun, 28 Jul 2024 23:04:45 -0000 (UTC)) it happened Cursitor >>>>Doom <cd999666@notformail.com> wrote in <v86iqd$3n74$2@dont-email.me>:

    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked >>>>>> wheels of wagons seemed to turn backwards in certain speed ranges.

    I can get my head around that kind of sampling no problem. But there's >>>>>nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a >>>>>mixer. Come to think of it, I don't really know anything about them other >>>>>than you input two different frequency signals which intermodulate and you >>>>>get the sum and the difference of them at the output; then filter for the >>>>>one you need. Is this intermodulation some form of sampling?

    Consider a simple PLL with a sampling gate as phase discriminator.
    When the frequencies are equal the output is some DC value, its amplitude depending on the phase difference.

    When one frequency goes a bit up, the output is the difference frequency. >>>>etc...

    I don't see the relevance here. If by 'sampling gate' you mean 'sample
    & hold' - which I assume you do - that's a different part of the loop >>>altogether from the part labled 'sampler' in the block diagram.

    Idujno,Ifind that diagram very much crap, more a block diagram

    Yes, it's a block diagram which shows the device labeled as a
    "sampler" comes before the phase detector, after which comes the
    sample and hold part.

    I wonder, did you EVER design any electronics?

    No. And I've never made any secret of that here.

    Try building a sampling circuit, or that instrument you are carrying on about >>to get a feel for what counts, so you CAN do fast fault finding.
    Else endless blur makes you see nothing.
    Should take 10 minutes to fix the thing if you did not damage it before hand.

    I can't fix it if I don't fully understand what it does, hence the
    original question.
    Anyway, it's clear that regardless of what HP call the thing, it's
    just a harmonic mixer and if I proceed on that basis, I should be able
    to trace the issue.

    So, as to that block diagram
    They come in with 177 to 187 MHz to one side of 'sampler'
    and with 2.3 GHz to 6.1 GHz on the other side of 'sampler'.

    Sampler is followed by a 70 MHz lowpass
    And then out the 'sampler' comes 20 MHz to 30 MHz

    input is 10 MHz wide, output is 10 MHz wide, so far so good, if it is some mixer
    But mixing GHz with a few MHz does not give MHz signals
    It gets worse, the output of 20 to 30 MHz is then devided by 2 to 10 to 15 MHz and compared to 15 to 30 MHz divided by 2 from 'syntesizer' and used to drive 'FM coil driver'.
    and looks like used to FM (FM coil driver) modulate that 2.3 to 6.1 GHz oscillator.
    Now in case of FM modulation sidebands will be all over the place (all just a few MHz apart in this case)...
    Now here comes a clue, those sidebands WILL interact with the 177 to 187 MHz Not much but some...
    OTOH not all documentation is written by the designers, so maybe the numbers are different...
    ;-)
    Setup seem bizarre, better get a cheap Chinese meter from ebay.

    If you do not design anything why bother with old rusty boat anchors...
    I do not have any and all stuff works here.
    Start building something simple, and take it from there.
    Crystal radio?

    /

    Do not get hung up in math.
    maaaz is used everywhere and people think it is reality, like 'space is curved' crap.
    Get a decent analog scope and start with some radios or transmitters, or maybe a light bulb, or whatever have you.

    As a kid I started with checking if the 4.5 battery was full with my tongue, build my own scope many years later...
    I did not even have a multimeter, just a uA meter and some resistors...
    And yes I had a home build TV running in my room.
    Later after school working for a power company I designed and build my own vidicon portabe camera, changed jobs gave me a job at the national TV network..
    Fault finding:? the show must go on - NOW - regardless of stressed producers... artists waiting.. whole country watching,
    global networks, remote locations, no black screen allowed...
    Video, audio, tape recording, 35 mm film, projectors, film scanners, studios were something else those days.
    Boat anchors? you have not seen it yet :-) Rooms full of tubes... monitors, scopes on each video recorder, synchronisation stuff..
    Now a youtube channel is all you need and a few dollies ($$) will buy you all you need.
    Some equipment we used back then did cost a few million...

    Oh well, OK start with a crystal radio perhaps... That is what I did, oh and tubes and record players ... oh and ..
    that was in primary school days, then in highschool: amplifier for the school band and a FM radio transmitter for the music we made..

    electronics is fun,
    programming can be too, but that came much later...

    It is remarkable that when in those eighties US landed on the moon, I was in the TV head control room here to relay it to the people in my country,
    and now with all them sup[p]er computahs astronuts are stuck due to some helium leaks in some thrusters endlessly driving around the block.

    Now with US IQ dropping to single digit values and as China already got stuff back from the backside of the moon..
    where will it go...
    Will that US union fall apart? Will it get so hot they will all flee to Canada?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to alien@comet.invalid on Mon Jul 29 16:04:40 2024
    On a sunny day (Mon, 29 Jul 2024 15:56:22 GMT) it happened Jan Panteltje <alien@comet.invalid> wrote in <v88e38$h3ik$1@solani.org>:

    On a sunny day (Mon, 29 Jul 2024 12:50:33 +0100) it happened Cursitor Doom ><cd@notformail.com> wrote in <p80fajltc50rajhib7dqjn6mbni6d8ko6q@4ax.com>:

    On Mon, 29 Jul 2024 11:30:08 GMT, Jan Panteltje <alien@comet.invalid> >>wrote:

    On a sunny day (Mon, 29 Jul 2024 12:06:31 +0100) it happened Cursitor Doom >>><cd@notformail.com> wrote in <7qteaj94r7l8n9ct4h16kviugq6shkp384@4ax.com>: >>>
    On Mon, 29 Jul 2024 05:24:31 GMT, Jan Panteltje <alien@comet.invalid> >>>>wrote:

    On a sunny day (Sun, 28 Jul 2024 23:04:45 -0000 (UTC)) it happened Cursitor
    Doom <cd999666@notformail.com> wrote in <v86iqd$3n74$2@dont-email.me>: >>>>>
    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked >>>>>>> wheels of wagons seemed to turn backwards in certain speed ranges. >>>>>>
    I can get my head around that kind of sampling no problem. But there's >>>>>>nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a >>>>>>mixer. Come to think of it, I don't really know anything about them other >>>>>>than you input two different frequency signals which intermodulate and you
    get the sum and the difference of them at the output; then filter for the >>>>>>one you need. Is this intermodulation some form of sampling?

    Consider a simple PLL with a sampling gate as phase discriminator. >>>>>When the frequencies are equal the output is some DC value, its amplitude depending on the phase difference.

    When one frequency goes a bit up, the output is the difference frequency. >>>>>etc...

    I don't see the relevance here. If by 'sampling gate' you mean 'sample >>>>& hold' - which I assume you do - that's a different part of the loop >>>>altogether from the part labled 'sampler' in the block diagram.

    Idujno,Ifind that diagram very much crap, more a block diagram

    Yes, it's a block diagram which shows the device labeled as a
    "sampler" comes before the phase detector, after which comes the
    sample and hold part.

    I wonder, did you EVER design any electronics?

    No. And I've never made any secret of that here.

    Try building a sampling circuit, or that instrument you are carrying on about
    to get a feel for what counts, so you CAN do fast fault finding.
    Else endless blur makes you see nothing.
    Should take 10 minutes to fix the thing if you did not damage it before hand.

    I can't fix it if I don't fully understand what it does, hence the
    original question.
    Anyway, it's clear that regardless of what HP call the thing, it's
    just a harmonic mixer and if I proceed on that basis, I should be able
    to trace the issue.

    So, as to that block diagram
    They come in with 177 to 187 MHz to one side of 'sampler'
    and with 2.3 GHz to 6.1 GHz on the other side of 'sampler'.

    Sampler is followed by a 70 MHz lowpass
    And then out the 'sampler' comes 20 MHz to 30 MHz

    input is 10 MHz wide, output is 10 MHz wide, so far so good, if it is some mixer
    But mixing GHz with a few MHz does not give MHz signals
    It gets worse, the output of 20 to 30 MHz is then devided by 2 to 10 to 15 MHz >and compared to 15 to 30 MHz divided by 2 from 'syntesizer' and used to drive 'FM coil driver'.
    and looks like used to FM (FM coil driver) modulate that 2.3 to 6.1 GHz oscillator.
    Now in case of FM modulation sidebands will be all over the place (all just a few MHz apart in this case)...
    Now here comes a clue, those sidebands WILL interact with the 177 to 187 MHz >Not much but some...
    OTOH not all documentation is written by the designers, so maybe the numbers are different...
    ;-)
    Setup seem bizarre, better get a cheap Chinese meter from ebay.

    If you do not design anything why bother with old rusty boat anchors...
    I do not have any and all stuff works here.
    Start building something simple, and take it from there.
    Crystal radio?

    /

    Do not get hung up in math.
    maaaz is used everywhere and people think it is reality, like 'space is curved' crap.
    Get a decent analog scope and start with some radios or transmitters, or maybe a light bulb, or whatever have you.

    As a kid I started with checking if the 4.5 battery was full with my tongue, build my own scope many years later...
    I did not even have a multimeter, just a uA meter and some resistors...
    And yes I had a home build TV running in my room.
    Later after school working for a power company I designed and build my own vidicon portabe camera, changed jobs gave me a job at
    the national TV network..
    Fault finding:? the show must go on - NOW - regardless of stressed producers... artists waiting.. whole country watching,
    global networks, remote locations, no black screen allowed...
    Video, audio, tape recording, 35 mm film, projectors, film scanners, studios were something else those days.
    Boat anchors? you have not seen it yet :-) Rooms full of tubes... monitors, scopes on each video recorder, synchronisation
    stuff..
    Now a youtube channel is all you need and a few dollies ($$) will buy you all you need.
    Some equipment we used back then did cost a few million...

    Oh well, OK start with a crystal radio perhaps... That is what I did, oh and tubes and record players ... oh and ..
    that was in primary school days, then in highschool: amplifier for the school band and a FM radio transmitter for the music we
    made..

    electronics is fun,
    programming can be too, but that came much later...

    It is remarkable that when in those eighties US landed on the moon, I was in the TV head control room here to relay it to the

    Oops, sixties that was, time flies, unlike BO[i]NG capsules and planes ...

    hehe
    :-)

    people in my country,
    and now with all them sup[p]er computahs astronuts are stuck due to some helium leaks in some thrusters endlessly driving
    around the block.

    Now with US IQ dropping to single digit values and as China already got stuff back from the backside of the moon..
    where will it go...
    Will that US union fall apart? Will it get so hot they will all flee to Canada?




    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Mon Jul 29 09:06:48 2024
    On Mon, 29 Jul 2024 12:50:33 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Mon, 29 Jul 2024 11:30:08 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Mon, 29 Jul 2024 12:06:31 +0100) it happened Cursitor Doom >><cd@notformail.com> wrote in <7qteaj94r7l8n9ct4h16kviugq6shkp384@4ax.com>:

    On Mon, 29 Jul 2024 05:24:31 GMT, Jan Panteltje <alien@comet.invalid> >>>wrote:

    On a sunny day (Sun, 28 Jul 2024 23:04:45 -0000 (UTC)) it happened Cursitor >>>>Doom <cd999666@notformail.com> wrote in <v86iqd$3n74$2@dont-email.me>:

    On Sun, 28 Jul 2024 20:28:25 -0000 (UTC), Phil Hobbs wrote:

    Stroboscopic sampling is familiar from old Westerns, where the spoked >>>>>> wheels of wagons seemed to turn backwards in certain speed ranges.

    I can get my head around that kind of sampling no problem. But there's >>>>>nothing analagous to that going on with this device AFAICS.
    Perhaps I don't have a good enough understanding of what happens in a >>>>>mixer. Come to think of it, I don't really know anything about them other >>>>>than you input two different frequency signals which intermodulate and you >>>>>get the sum and the difference of them at the output; then filter for the >>>>>one you need. Is this intermodulation some form of sampling?

    Consider a simple PLL with a sampling gate as phase discriminator.
    When the frequencies are equal the output is some DC value, its amplitude depending on the phase difference.

    When one frequency goes a bit up, the output is the difference frequency. >>>>etc...

    I don't see the relevance here. If by 'sampling gate' you mean 'sample
    & hold' - which I assume you do - that's a different part of the loop >>>altogether from the part labled 'sampler' in the block diagram.

    Idujno,Ifind that diagram very much crap, more a block diagram

    Yes, it's a block diagram which shows the device labeled as a
    "sampler" comes before the phase detector, after which comes the
    sample and hold part.

    I wonder, did you EVER design any electronics?

    No. And I've never made any secret of that here.

    Try building a sampling circuit, or that instrument you are carrying on about >>to get a feel for what counts, so you CAN do fast fault finding.
    Else endless blur makes you see nothing.
    Should take 10 minutes to fix the thing if you did not damage it before hand.

    I can't fix it if I don't fully understand what it does, hence the
    original question.
    Anyway, it's clear that regardless of what HP call the thing, it's
    just a harmonic mixer and if I proceed on that basis, I should be able
    to trace the issue.

    This is actually a pretty good book:

    https://www.amazon.com/Signals-Systems-Dummies-Mark-Wickert/dp/111847581X

    It's not as simple as it sounds, but a pretty good read.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Mon Jul 29 09:29:04 2024
    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened Cursitor >Doom <cd999666@notformail.com> wrote in <v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. The >>signal from the LHS is passed through a very fast diode which generates >>harmonics from that fundamental. The signal from the RHS is unmodified and >>mixed with the desired harmonic to give the necessary output signal which >>is then filtered to get rid of the unwanted mixing products. If that's all >>correct, as I believe it is, where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode
    thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a
    pentode. Or even a single diode. All do some flavor of multiplying.

    Some mixers inherently multiply a signal by a square wave, which
    resembles other multiplier-type things once you lowpass filter the
    output. That's a "synchronous detector", which we usually do in an
    FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Mon Jul 29 09:15:47 2024
    On Mon, 29 Jul 2024 10:05:56 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Sun, 28 Jul 2024 19:16:10 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 28 Jul 2024 21:40:41 -0000 (UTC), Cursitor Doom >><cd999666@notformail.com> wrote:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. The >>>signal from the LHS is passed through a very fast diode which generates >>>harmonics from that fundamental. The signal from the RHS is unmodified and >>>mixed with the desired harmonic to give the necessary output signal which >>>is then filtered to get rid of the unwanted mixing products. If that's all >>>correct, as I believe it is, where does any *sampling* come into it?

    Mixing = sampling = multiplication.

    Apples = oranges = pears is an equally valid statement!

    In our world, some understanding of "signals and systems" is
    fundamental. Summing, multiplying, filtering, correlating, thinking
    freely in time and frequency domains. S+S is not instantly obvious,
    and takes some work to understand, but ultimately having instincts and
    tools for this stuff is valuable and great fun.

    LT Spice can help visualize cases, since you can see both waveforms
    and FFTs.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Mon Jul 29 18:08:20 2024
    On Mon, 29 Jul 2024 09:29:04 -0700, john larkin wrote:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in >><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. The >>>signal from the LHS is passed through a very fast diode which generates >>>harmonics from that fundamental. The signal from the RHS is unmodified >>>and mixed with the desired harmonic to give the necessary output signal >>>which is then filtered to get rid of the unwanted mixing products. If >>>that's all correct, as I believe it is, where does any *sampling* come >>>into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode
    thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a
    pentode. Or even a single diode. All do some flavor of multiplying.

    Some mixers inherently multiply a signal by a square wave, which
    resembles other multiplier-type things once you lowpass filter the
    output. That's a "synchronous detector", which we usually do in an FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals.

    According to the block diagram, the output of the sampler-cum-harmonic
    mixer should be between 20Mhz and 30Mhz. However, when I insert a tee into
    that part of the loop, all I'm seeing is a bunch of random garbage signals
    in the range of 650kHz to about 9Mhz (fortunately I've a spare spectrum analyser to see this with). That unexpected result indicates there's most likely something wrong with the "sampler" *or* one or both of the signals
    going into it. However, before I can start to investigate that part of the loop, I needed to know what the sampler *should* be doing. Now I know it's
    just HP's fancy term for a harmonic mixer I have a much better
    understanding of the circuit.
    My thanks to all who contributed here.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to All on Tue Jul 30 05:16:24 2024
    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john larkin <jlarkin_highland_tech> wrote in <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened Cursitor >>Doom <cd999666@notformail.com> wrote in <v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. The >>>signal from the LHS is passed through a very fast diode which generates >>>harmonics from that fundamental. The signal from the RHS is unmodified and >>>mixed with the desired harmonic to give the necessary output signal which >>>is then filtered to get rid of the unwanted mixing products. If that's all >>>correct, as I believe it is, where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode
    thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a
    pentode. Or even a single diode. All do some flavor of multiplying.

    Some mixers inherently multiply a signal by a square wave, which
    resembles other multiplier-type things once you lowpass filter the
    output. That's a "synchronous detector", which we usually do in an
    FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals.

    A the word 'mixer' in RF is not the same as a multiplier,
    Multipliers are like harmonic generating stages
    say you have a 1 MHz distorted sine wave
    and then a second stage tuned at 3 MHz,.. turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Jan Panteltje on Tue Jul 30 08:58:35 2024
    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john larkin <jlarkin_highland_tech> wrote in <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid> >>wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>Cursitor Doom <cd999666@notformail.com> wrote in >>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out.
    The signal from the LHS is passed through a very fast diode which >>>>generates harmonics from that fundamental. The signal from the RHS is >>>>unmodified and mixed with the desired harmonic to give the necessary >>>>output signal which is then filtered to get rid of the unwanted mixing >>>>products. If that's all correct, as I believe it is, where does any >>>>*sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode
    thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a
    pentode. Or even a single diode. All do some flavor of multiplying.

    Some mixers inherently multiply a signal by a square wave, which
    resembles other multiplier-type things once you lowpass filter the
    output. That's a "synchronous detector", which we usually do in an FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz distorted sine wave and then a second stage tuned at 3 MHz,.. turned to
    third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean something
    which 'sniffs' a small amount of a signal for testing purposes. Like a few turns of wire around a transmission line will 'sniff' a small sample of
    what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the manner
    a sampling oscilloscope works. That's what threw me. I tend to interpret
    things very literally. :(

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to Cursitor Doom on Tue Jul 30 20:30:27 2024
    On 30/07/2024 6:58 pm, Cursitor Doom wrote:
    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john larkin
    <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v86dsp$3n74$1@dont-email.me>:

    <snip>

    I think in this context, HP is using the term "sampler" to mean something which 'sniffs' a small amount of a signal for testing purposes. Like a few turns of wire around a transmission line will 'sniff' a small sample of what's going on in the line.

    Wrong. The kind of sampling going on produces an output at a different frequency than that of the signal being tested/monitored/sampled.

    That implies some kind of non-linear interaction with a "sampling" input
    at yet another frequency.

    --
    Bill Sloman, Sydney

    Where I went wrong was rigidly thinking HP meant 'sampling' in the manner
    a sampling oscilloscope works. That's what threw me. I tend to interpret things very literally. :(


    --
    This email has been checked for viruses by Norton antivirus software. www.norton.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to Doom on Tue Jul 30 10:36:51 2024
    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened Cursitor Doom <cd999666@notformail.com> wrote in <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john larkin
    <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid> >>>wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. >>>>>The signal from the LHS is passed through a very fast diode which >>>>>generates harmonics from that fundamental. The signal from the RHS is >>>>>unmodified and mixed with the desired harmonic to give the necessary >>>>>output signal which is then filtered to get rid of the unwanted mixing >>>>>products. If that's all correct, as I believe it is, where does any >>>>>*sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a >>>pentode. Or even a single diode. All do some flavor of multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>resembles other multiplier-type things once you lowpass filter the >>>output. That's a "synchronous detector", which we usually do in an FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz
    distorted sine wave and then a second stage tuned at 3 MHz,.. turned to
    third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean something >which 'sniffs' a small amount of a signal for testing purposes. Like a few >turns of wire around a transmission line will 'sniff' a small sample of >what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the manner
    a sampling oscilloscope works. That's what threw me. I tend to interpret >things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across with google.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Jan Panteltje on Tue Jul 30 11:20:47 2024
    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid> >>>>wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. >>>>>>The signal from the LHS is passed through a very fast diode which >>>>>>generates harmonics from that fundamental. The signal from the RHS >>>>>>is unmodified and mixed with the desired harmonic to give the >>>>>>necessary output signal which is then filtered to get rid of the >>>>>>unwanted mixing products. If that's all correct, as I believe it is, >>>>>>where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>>thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a >>>>pentode. Or even a single diode. All do some flavor of multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>resembles other multiplier-type things once you lowpass filter the >>>>output. That's a "synchronous detector", which we usually do in an >>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz
    distorted sine wave and then a second stage tuned at 3 MHz,.. turned
    to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean
    something which 'sniffs' a small amount of a signal for testing
    purposes. Like a few turns of wire around a transmission line will
    'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the
    manner a sampling oscilloscope works. That's what threw me. I tend to >>interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across
    with google.

    It's the HP8566B - a very well known lab-grade analyser of the day which
    many RF designers still use. There is a *ton* of service info on this
    model online. However, I have not been able to see a *proper* schematic
    for the "sampler" in the A11A5 board which is where the issue is.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to All on Tue Jul 30 11:01:17 2024
    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened Cursitor >Doom <cd999666@notformail.com> wrote in <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid> >>>>>>wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>AFAICT, there's are two signals into this thing and one signal out. >>>>>>>>The signal from the LHS is passed through a very fast diode which >>>>>>>>generates harmonics from that fundamental. The signal from the RHS >>>>>>>>is unmodified and mixed with the desired harmonic to give the >>>>>>>>necessary output signal which is then filtered to get rid of the >>>>>>>>unwanted mixing products. If that's all correct, as I believe it is, >>>>>>>>where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>>>>thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a >>>>>>pentode. Or even a single diode. All do some flavor of multiplying. >>>>>>
    Some mixers inherently multiply a signal by a square wave, which >>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals. >>>>>
    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz >>>>> distorted sine wave and then a second stage tuned at 3 MHz,.. turned >>>>> to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>something which 'sniffs' a small amount of a signal for testing >>>>purposes. Like a few turns of wire around a transmission line will >>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>manner a sampling oscilloscope works. That's what threw me. I tend to >>>>interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across
    with google.

    It's the HP8566B - a very well known lab-grade analyser of the day which >>many RF designers still use. There is a *ton* of service info on this
    model online. However, I have not been able to see a *proper* schematic
    for the "sampler" in the A11A5 board which is where the issue is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr-programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B,%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits
    I will have a look at the hundreds of pages, will take some time.
    I presume you have these?
    Took 10 seconds to find with google

    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to 12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium reference)
    Also build a small downmixer so it can see 2.4 GHz too
    Plenty free spectral display programs online for it,
    I wrote my own:
    https://panteltje.nl/panteltje/xpsa/index.html
    it also has an 'harmonic' button to look for the next harmonic when you select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi..
    The RTL_SDR sticks can even receive GPS signals...
    https://panteltje.nl/pub/run_50_outside_2728000.gif
    uses this guys software<;
    http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr-domain.html

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use for my Raspberry)
    and there are several audio programs with spectrum display

    There are so many possibilities...

    HP always put the theory notes in the HP Journal, so I'd suggest
    searching there for the HP8566B, in the issues around when the
    instrument was first introduced.

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to Doom on Tue Jul 30 14:51:10 2024
    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened Cursitor Doom <cd999666@notformail.com> wrote in <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid> >>>>>wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. >>>>>>>The signal from the LHS is passed through a very fast diode which >>>>>>>generates harmonics from that fundamental. The signal from the RHS >>>>>>>is unmodified and mixed with the desired harmonic to give the >>>>>>>necessary output signal which is then filtered to get rid of the >>>>>>>unwanted mixing products. If that's all correct, as I believe it is, >>>>>>>where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>>>thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a >>>>>pentode. Or even a single diode. All do some flavor of multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>resembles other multiplier-type things once you lowpass filter the >>>>>output. That's a "synchronous detector", which we usually do in an >>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals. >>>>
    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz
    distorted sine wave and then a second stage tuned at 3 MHz,.. turned
    to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean
    something which 'sniffs' a small amount of a signal for testing
    purposes. Like a few turns of wire around a transmission line will >>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the
    manner a sampling oscilloscope works. That's what threw me. I tend to >>>interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across
    with google.

    It's the HP8566B - a very well known lab-grade analyser of the day which
    many RF designers still use. There is a *ton* of service info on this
    model online. However, I have not been able to see a *proper* schematic
    for the "sampler" in the A11A5 board which is where the issue is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr-programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B,%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits
    I will have a look at the hundreds of pages, will take some time.
    I presume you have these?
    Took 10 seconds to find with google

    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to 12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium reference)
    Also build a small downmixer so it can see 2.4 GHz too
    Plenty free spectral display programs online for it,
    I wrote my own:
    https://panteltje.nl/panteltje/xpsa/index.html
    it also has an 'harmonic' button to look for the next harmonic when you select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi..
    The RTL_SDR sticks can even receive GPS signals...
    https://panteltje.nl/pub/run_50_outside_2728000.gif
    uses this guys software<;
    http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr-domain.html

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use for my Raspberry)
    and there are several audio programs with spectrum display

    There are so many possibilities...

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Jan Panteltje on Tue Jul 30 15:11:35 2024
    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>out. The signal from the LHS is passed through a very fast diode >>>>>>>>which generates harmonics from that fundamental. The signal from >>>>>>>>the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>the necessary output signal which is then filtered to get rid of >>>>>>>>the unwanted mixing products. If that's all correct, as I believe >>>>>>>>it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>>>>thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a >>>>>>pentode. Or even a single diode. All do some flavor of multiplying. >>>>>>
    Some mixers inherently multiply a signal by a square wave, which >>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz >>>>> distorted sine wave and then a second stage tuned at 3 MHz,.. turned >>>>> to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>something which 'sniffs' a small amount of a signal for testing >>>>purposes. Like a few turns of wire around a transmission line will >>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>manner a sampling oscilloscope works. That's what threw me. I tend to >>>>interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across
    with google.

    It's the HP8566B - a very well known lab-grade analyser of the day which >>many RF designers still use. There is a *ton* of service info on this
    model online. However, I have not been able to see a *proper* schematic
    for the "sampler" in the A11A5 board which is where the issue is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/
    hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/
    HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B,
    %208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages, will
    take some time.
    I presume you have these?
    Took 10 seconds to find with google

    Yes, I have all of those and more. I think altogether there are 7 very
    large manuals for this analyser. However, I've not been able to find a
    single actual schematic which gives component level detail of what they
    call the "sampler" - and that's unusual, as they've given a great deal of attention to providing very full service details in all other respects.


    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to
    12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium
    reference)
    Also build a small downmixer so it can see 2.4 GHz too Plenty free
    spectral display programs online for it,
    I wrote my own:
    https://panteltje.nl/panteltje/xpsa/index.html
    it also has an 'harmonic' button to look for the next harmonic when you select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi..
    The RTL_SDR sticks can even receive GPS signals...
    https://panteltje.nl/pub/run_50_outside_2728000.gif uses this guys
    software<;
    http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr-
    domain.html

    I wouldn't trust myself to build something like that. I'd get spurious
    signals and wouldn't know if they're truly spurious or not. Plus I like
    boat anchors and their imposing presence. I also like lots of knobs,
    because lots of knobs = no menu system and no menu means it's a lot easier
    to find what you want.

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use
    for my Raspberry)

    I have bespoke audio generators. Boat anchors again.

    and there are several audio programs with spectrum display

    I have an HP audio spectrum analyser - another monster - which I could
    power up if necessary for that purpose. It would probably go bang, though. Hasn't been switched on for years, you see.

    There are so many possibilities...

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Joe Gwinn on Tue Jul 30 15:13:47 2024
    On Tue, 30 Jul 2024 11:01:17 -0400, Joe Gwinn wrote:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in >><v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>>out. The signal from the LHS is passed through a very fast diode >>>>>>>>>which generates harmonics from that fundamental. The signal from >>>>>>>>>the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>>the necessary output signal which is then filtered to get rid of >>>>>>>>>the unwanted mixing products. If that's all correct, as I believe >>>>>>>>>it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>like a pentode. Or even a single diode. All do some flavor of >>>>>>>multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1
    MHz distorted sine wave and then a second stage tuned at 3 MHz,..
    turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>something which 'sniffs' a small amount of a signal for testing >>>>>purposes. Like a few turns of wire around a transmission line will >>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>manner a sampling oscilloscope works. That's what threw me. I tend to >>>>>interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across
    with google.

    It's the HP8566B - a very well known lab-grade analyser of the day
    which many RF designers still use. There is a *ton* of service info on >>>this model online. However, I have not been able to see a *proper* >>>schematic for the "sampler" in the A11A5 board which is where the issue >>>is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/ hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/ HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, %208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages, will >>take some time.
    I presume you have these?
    Took 10 seconds to find with google

    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to
    12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium
    reference)
    Also build a small downmixer so it can see 2.4 GHz too Plenty free
    spectral display programs online for it,
    I wrote my own:
    https://panteltje.nl/panteltje/xpsa/index.html
    it also has an 'harmonic' button to look for the next harmonic when you >>select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi..
    The RTL_SDR sticks can even receive GPS signals...
    https://panteltje.nl/pub/run_50_outside_2728000.gif uses this guys
    software<;
    http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr- domain.html

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use
    for my Raspberry)
    and there are several audio programs with spectrum display

    There are so many possibilities...

    HP always put the theory notes in the HP Journal, so I'd suggest
    searching there for the HP8566B, in the issues around when the
    instrument was first introduced.

    This analyser is well over 30 years old, so whatever's gone wrong is most likely age-related and wouldn't have come to light for many years.
    Fortunately there's a lot of info out there - *if* you can find it!


    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to cd999666@notformail.com on Tue Jul 30 13:46:06 2024
    On Tue, 30 Jul 2024 15:13:47 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 11:01:17 -0400, Joe Gwinn wrote:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened >>>Cursitor Doom <cd999666@notformail.com> wrote in >>><v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>out. The signal from the LHS is passed through a very fast diode >>>>>>>>>>which generates harmonics from that fundamental. The signal from >>>>>>>>>>the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>>>the necessary output signal which is then filtered to get rid of >>>>>>>>>>the unwanted mixing products. If that's all correct, as I believe >>>>>>>>>>it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>like a pentode. Or even a single diode. All do some flavor of >>>>>>>>multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>something which 'sniffs' a small amount of a signal for testing >>>>>>purposes. Like a few turns of wire around a transmission line will >>>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>manner a sampling oscilloscope works. That's what threw me. I tend to >>>>>>interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across >>>>> with google.

    It's the HP8566B - a very well known lab-grade analyser of the day >>>>which many RF designers still use. There is a *ton* of service info on >>>>this model online. However, I have not been able to see a *proper* >>>>schematic for the "sampler" in the A11A5 board which is where the issue >>>>is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/ >hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- >programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/ >HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, >%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages, will >>>take some time.
    I presume you have these?
    Took 10 seconds to find with google

    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to
    12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium >>>reference)
    Also build a small downmixer so it can see 2.4 GHz too Plenty free >>>spectral display programs online for it,
    I wrote my own:
    https://panteltje.nl/panteltje/xpsa/index.html
    it also has an 'harmonic' button to look for the next harmonic when you >>>select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi..
    The RTL_SDR sticks can even receive GPS signals...
    https://panteltje.nl/pub/run_50_outside_2728000.gif uses this guys
    software<;
    http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr- >domain.html

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use >>>for my Raspberry)
    and there are several audio programs with spectrum display

    There are so many possibilities...

    HP always put the theory notes in the HP Journal, so I'd suggest
    searching there for the HP8566B, in the issues around when the
    instrument was first introduced.

    This analyser is well over 30 years old, so whatever's gone wrong is most >likely age-related and wouldn't have come to light for many years. >Fortunately there's a lot of info out there - *if* you can find it!

    On the lack of a schematic, I did dig into how it worked many years
    ago, and as I recall it was based of some fancy abuse of a slotted
    rectangular waveguide which supported various orthogonal modes - this
    cannot be described by any lumped-parameter circuit.

    Try this:

    US4647795A, Travelling wave sampler, Agoston Agoston, Beaverton, Oreg. Tektronix, Inc., Beaverton, Oreg. granted 3 March 1987.

    .<https://patents.google.com/patent/US4647795A>

    It does have schematics, in a manner of speaking.

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to cd999666@notformail.com on Tue Jul 30 10:39:37 2024
    On Tue, 30 Jul 2024 08:58:35 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john larkin
    <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid> >>>wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. >>>>>The signal from the LHS is passed through a very fast diode which >>>>>generates harmonics from that fundamental. The signal from the RHS is >>>>>unmodified and mixed with the desired harmonic to give the necessary >>>>>output signal which is then filtered to get rid of the unwanted mixing >>>>>products. If that's all correct, as I believe it is, where does any >>>>>*sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a >>>pentode. Or even a single diode. All do some flavor of multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>resembles other multiplier-type things once you lowpass filter the >>>output. That's a "synchronous detector", which we usually do in an FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz
    distorted sine wave and then a second stage tuned at 3 MHz,.. turned to
    third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean something >which 'sniffs' a small amount of a signal for testing purposes. Like a few >turns of wire around a transmission line will 'sniff' a small sample of >what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the manner
    a sampling oscilloscope works. That's what threw me. I tend to interpret >things very literally. :(

    The sampler in the SA schematic is precisely the sort of sampler used
    in a sampling scope. It contains a step-recovery diode impulse
    generator and no doubt some sampling diodes.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From piglet@21:1/5 to Cursitor Doom on Tue Jul 30 17:51:29 2024
    Cursitor Doom <cd999666@notformail.com> wrote:
    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid> >>>>> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. >>>>>>> The signal from the LHS is passed through a very fast diode which >>>>>>> generates harmonics from that fundamental. The signal from the RHS >>>>>>> is unmodified and mixed with the desired harmonic to give the
    necessary output signal which is then filtered to get rid of the >>>>>>> unwanted mixing products. If that's all correct, as I believe it is, >>>>>>> where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>>> thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a
    pentode. Or even a single diode. All do some flavor of multiplying.

    Some mixers inherently multiply a signal by a square wave, which
    resembles other multiplier-type things once you lowpass filter the
    output. That's a "synchronous detector", which we usually do in an
    FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals. >>>>
    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz
    distorted sine wave and then a second stage tuned at 3 MHz,.. turned
    to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean
    something which 'sniffs' a small amount of a signal for testing
    purposes. Like a few turns of wire around a transmission line will
    'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the
    manner a sampling oscilloscope works. That's what threw me. I tend to
    interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across
    with google.

    It's the HP8566B - a very well known lab-grade analyser of the day which
    many RF designers still use. There is a *ton* of service info on this
    model online. However, I have not been able to see a *proper* schematic
    for the "sampler" in the A11A5 board which is where the issue is.


    The schematic of A11U1 might only show three diodes, the srd and two
    schottkys - the magic is in the physical construction. Flip chips, ceramic substrate, artfully designed micro strips and what not. I doubt that
    assembly is amenable to repair.

    The HP8566 seems to be notorious for fiendish YTO unlock problems which
    more often than not end up being trivial preset pot wiper lifts or aged capacitors in the YIG coil drivers.

    --
    piglet

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From piglet@21:1/5 to Joe Gwinn on Tue Jul 30 17:51:50 2024
    Joe Gwinn <joegwinn@comcast.net> wrote:
    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened Cursitor >> Doom <cd999666@notformail.com> wrote in <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid> >>>>>>> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. >>>>>>>>> The signal from the LHS is passed through a very fast diode which >>>>>>>>> generates harmonics from that fundamental. The signal from the RHS >>>>>>>>> is unmodified and mixed with the desired harmonic to give the >>>>>>>>> necessary output signal which is then filtered to get rid of the >>>>>>>>> unwanted mixing products. If that's all correct, as I believe it is, >>>>>>>>> where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>>>>> thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a >>>>>>> pentode. Or even a single diode. All do some flavor of multiplying. >>>>>>>
    Some mixers inherently multiply a signal by a square wave, which >>>>>>> resembles other multiplier-type things once you lowpass filter the >>>>>>> output. That's a "synchronous detector", which we usually do in an >>>>>>> FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals. >>>>>>
    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz >>>>>> distorted sine wave and then a second stage tuned at 3 MHz,.. turned >>>>>> to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean
    something which 'sniffs' a small amount of a signal for testing
    purposes. Like a few turns of wire around a transmission line will
    'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the
    manner a sampling oscilloscope works. That's what threw me. I tend to >>>>> interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across
    with google.

    It's the HP8566B - a very well known lab-grade analyser of the day which >>> many RF designers still use. There is a *ton* of service info on this
    model online. However, I have not been able to see a *proper* schematic
    for the "sampler" in the A11A5 board which is where the issue is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr-programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B,%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits
    I will have a look at the hundreds of pages, will take some time.
    I presume you have these?
    Took 10 seconds to find with google

    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to
    12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium reference) >> Also build a small downmixer so it can see 2.4 GHz too
    Plenty free spectral display programs online for it,
    I wrote my own:
    https://panteltje.nl/panteltje/xpsa/index.html
    it also has an 'harmonic' button to look for the next harmonic when you
    select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi..
    The RTL_SDR sticks can even receive GPS signals...
    https://panteltje.nl/pub/run_50_outside_2728000.gif
    uses this guys software<;
    http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr-domain.html

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use for my Raspberry)
    and there are several audio programs with spectrum display

    There are so many possibilities...

    HP always put the theory notes in the HP Journal, so I'd suggest
    searching there for the HP8566B, in the issues around when the
    instrument was first introduced.

    Joe Gwinn


    August 1979 - available many places including Hpmemoryproject and hparchive


    --
    piglet

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to piglet on Tue Jul 30 19:14:16 2024
    On Tue, 30 Jul 2024 17:51:29 -0000 (UTC), piglet wrote:

    Cursitor Doom <cd999666@notformail.com> wrote:
    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje
    <alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal >>>>>>>> out. The signal from the LHS is passed through a very fast diode >>>>>>>> which generates harmonics from that fundamental. The signal from >>>>>>>> the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>> the necessary output signal which is then filtered to get rid of >>>>>>>> the unwanted mixing products. If that's all correct, as I believe >>>>>>>> it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant
    diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing
    like a pentode. Or even a single diode. All do some flavor of
    multiplying.

    Some mixers inherently multiply a signal by a square wave, which
    resembles other multiplier-type things once you lowpass filter the >>>>>> output. That's a "synchronous detector", which we usually do in an >>>>>> FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two
    signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz >>>>> distorted sine wave and then a second stage tuned at 3 MHz,.. turned >>>>> to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean
    something which 'sniffs' a small amount of a signal for testing
    purposes. Like a few turns of wire around a transmission line will
    'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the
    manner a sampling oscilloscope works. That's what threw me. I tend to
    interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across
    with google.

    It's the HP8566B - a very well known lab-grade analyser of the day
    which many RF designers still use. There is a *ton* of service info on
    this model online. However, I have not been able to see a *proper*
    schematic for the "sampler" in the A11A5 board which is where the issue
    is.


    The schematic of A11U1 might only show three diodes, the srd and two schottkys - the magic is in the physical construction. Flip chips,hi
    ceramic substrate, artfully designed micro strips and what not. I doubt
    that assembly is amenable to repair.

    I hope it's not that, then!

    The HP8566 seems to be notorious for fiendish YTO unlock problems which
    more often than not end up being trivial preset pot wiper lifts or aged capacitors in the YIG coil drivers.

    True. There are all sorts of potential failure points. HP do provide about
    8 pages of charts covering the tuning range of the YIG oscillator and
    relating that to the corresponding M/N loop output signal. So one can, by reference to these charts, determine if the M/N signal and the YTO signal
    which come together at the "sampler" are both correctly correlated. If the values on the chart don't coincide with the measured values then obviously
    the loop can't lock. That's the next thing I'm going to check for.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Tue Jul 30 19:21:28 2024
    On Tue, 30 Jul 2024 10:39:37 -0700, john larkin wrote:

    On Tue, 30 Jul 2024 08:58:35 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid> >>>>wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. >>>>>>The signal from the LHS is passed through a very fast diode which >>>>>>generates harmonics from that fundamental. The signal from the RHS >>>>>>is unmodified and mixed with the desired harmonic to give the >>>>>>necessary output signal which is then filtered to get rid of the >>>>>>unwanted mixing products. If that's all correct, as I believe it is, >>>>>>where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>>thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a >>>>pentode. Or even a single diode. All do some flavor of multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>resembles other multiplier-type things once you lowpass filter the >>>>output. That's a "synchronous detector", which we usually do in an >>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz
    distorted sine wave and then a second stage tuned at 3 MHz,.. turned
    to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean
    something which 'sniffs' a small amount of a signal for testing
    purposes. Like a few turns of wire around a transmission line will
    'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the
    manner a sampling oscilloscope works. That's what threw me. I tend to >>interpret things very literally. :(

    The sampler in the SA schematic is precisely the sort of sampler used in
    a sampling scope. It contains a step-recovery diode impulse generator
    and no doubt some sampling diodes.

    How can you say that when you haven't seen the schematic? If you've been
    able to find it online somewhere then kindly post a link to it here.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Joe Gwinn on Tue Jul 30 19:26:56 2024
    On Tue, 30 Jul 2024 13:46:06 -0400, Joe Gwinn wrote:

    It does have schematics, in a manner of speaking.

    Quite.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to cd999666@notformail.com on Tue Jul 30 13:15:59 2024
    On Tue, 30 Jul 2024 19:21:28 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 10:39:37 -0700, john larkin wrote:

    On Tue, 30 Jul 2024 08:58:35 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje <alien@comet.invalid> >>>>>wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it.
    AFAICT, there's are two signals into this thing and one signal out. >>>>>>>The signal from the LHS is passed through a very fast diode which >>>>>>>generates harmonics from that fundamental. The signal from the RHS >>>>>>>is unmodified and mixed with the desired harmonic to give the >>>>>>>necessary output signal which is then filtered to get rid of the >>>>>>>unwanted mixing products. If that's all correct, as I believe it is, >>>>>>>where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>>>thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a >>>>>pentode. Or even a single diode. All do some flavor of multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>resembles other multiplier-type things once you lowpass filter the >>>>>output. That's a "synchronous detector", which we usually do in an >>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two signals. >>>>
    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz
    distorted sine wave and then a second stage tuned at 3 MHz,.. turned
    to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean
    something which 'sniffs' a small amount of a signal for testing
    purposes. Like a few turns of wire around a transmission line will >>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the
    manner a sampling oscilloscope works. That's what threw me. I tend to >>>interpret things very literally. :(

    The sampler in the SA schematic is precisely the sort of sampler used in
    a sampling scope. It contains a step-recovery diode impulse generator
    and no doubt some sampling diodes.

    How can you say that when you haven't seen the schematic? If you've been
    able to find it online somewhere then kindly post a link to it here.

    You posted an excerpt from the HP manual where the sampler is
    described.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Tue Jul 30 21:08:34 2024
    On Tue, 30 Jul 2024 13:15:59 -0700, john larkin wrote:

    On Tue, 30 Jul 2024 19:21:28 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 10:39:37 -0700, john larkin wrote:

    On Tue, 30 Jul 2024 08:58:35 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>out. The signal from the LHS is passed through a very fast diode >>>>>>>>which generates harmonics from that fundamental. The signal from >>>>>>>>the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>the necessary output signal which is then filtered to get rid of >>>>>>>>the unwanted mixing products. If that's all correct, as I believe >>>>>>>>it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>>>>thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a >>>>>>pentode. Or even a single diode. All do some flavor of multiplying. >>>>>>
    Some mixers inherently multiply a signal by a square wave, which >>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz >>>>> distorted sine wave and then a second stage tuned at 3 MHz,.. turned >>>>> to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>something which 'sniffs' a small amount of a signal for testing >>>>purposes. Like a few turns of wire around a transmission line will >>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>manner a sampling oscilloscope works. That's what threw me. I tend to >>>>interpret things very literally. :(

    The sampler in the SA schematic is precisely the sort of sampler used
    in a sampling scope. It contains a step-recovery diode impulse
    generator and no doubt some sampling diodes.

    How can you say that when you haven't seen the schematic? If you've been >>able to find it online somewhere then kindly post a link to it here.

    You posted an excerpt from the HP manual where the sampler is described.

    But you said:
    "The sampler in the SA schematic is precisely the sort of sampler used
    in a sampling scope."

    So you must have had sight of the schematic. I'd really appreciate it if
    you could post a link to it.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Tue Jul 30 13:31:20 2024
    On Tue, 30 Jul 2024 13:46:06 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 30 Jul 2024 15:13:47 -0000 (UTC), Cursitor Doom ><cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 11:01:17 -0400, Joe Gwinn wrote:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened >>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>><v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened >>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>>out. The signal from the LHS is passed through a very fast diode >>>>>>>>>>>which generates harmonics from that fundamental. The signal from >>>>>>>>>>>the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>>>>the necessary output signal which is then filtered to get rid of >>>>>>>>>>>the unwanted mixing products. If that's all correct, as I believe >>>>>>>>>>>it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>>like a pentode. Or even a single diode. All do some flavor of >>>>>>>>>multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>>something which 'sniffs' a small amount of a signal for testing >>>>>>>purposes. Like a few turns of wire around a transmission line will >>>>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>>manner a sampling oscilloscope works. That's what threw me. I tend to >>>>>>>interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across >>>>>> with google.

    It's the HP8566B - a very well known lab-grade analyser of the day >>>>>which many RF designers still use. There is a *ton* of service info on >>>>>this model online. However, I have not been able to see a *proper* >>>>>schematic for the "sampler" in the A11A5 board which is where the issue >>>>>is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/ >>hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- >>programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/ >>HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, >>%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages, will >>>>take some time.
    I presume you have these?
    Took 10 seconds to find with google

    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to >>>>12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium >>>>reference)
    Also build a small downmixer so it can see 2.4 GHz too Plenty free >>>>spectral display programs online for it,
    I wrote my own:
    https://panteltje.nl/panteltje/xpsa/index.html
    it also has an 'harmonic' button to look for the next harmonic when you >>>>select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi..
    The RTL_SDR sticks can even receive GPS signals...
    https://panteltje.nl/pub/run_50_outside_2728000.gif uses this guys
    software<;
    http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr- >>domain.html

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use >>>>for my Raspberry)
    and there are several audio programs with spectrum display

    There are so many possibilities...

    HP always put the theory notes in the HP Journal, so I'd suggest
    searching there for the HP8566B, in the issues around when the
    instrument was first introduced.

    This analyser is well over 30 years old, so whatever's gone wrong is most >>likely age-related and wouldn't have come to light for many years. >>Fortunately there's a lot of info out there - *if* you can find it!

    On the lack of a schematic, I did dig into how it worked many years
    ago, and as I recall it was based of some fancy abuse of a slotted >rectangular waveguide which supported various orthogonal modes - this
    cannot be described by any lumped-parameter circuit.

    Try this:

    US4647795A, Travelling wave sampler, Agoston Agoston, Beaverton, Oreg. >Tektronix, Inc., Beaverton, Oreg. granted 3 March 1987.

    .<https://patents.google.com/patent/US4647795A>

    It does have schematics, in a manner of speaking.

    Joe Gwinn

    I have an old HP sampling plugin that uses a machined block slotline
    structure. 3 GHz bandwidth as I recall.

    https://www.dropbox.com/scl/fo/3h4fvsfdh2youfd4kuolk/AIapB4g1x0BYRNXRIrAsrO8?rlkey=q5v7llkkk6yagr2w7h4c4kq8k&dl=0

    Agoston has a patent for a similar metal-block slotline sampler, but
    as far as I know Tek never manufactured it. The SD-series samplers
    were hybrids.

    https://www.dropbox.com/scl/fo/dnejszdktyc70se6frcdo/AM4vWFFsXPPF4Tw2ZeEm6m8?rlkey=xm82mhqn5mnrlv3l9j0pebj29&dl=0

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to Joe Gwinn on Tue Jul 30 23:17:01 2024
    On 7/30/24 19:46, Joe Gwinn wrote:
    On Tue, 30 Jul 2024 15:13:47 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 11:01:17 -0400, Joe Gwinn wrote:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened >>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje
    <alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>> AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>> out. The signal from the LHS is passed through a very fast diode >>>>>>>>>>> which generates harmonics from that fundamental. The signal from >>>>>>>>>>> the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>>>> the necessary output signal which is then filtered to get rid of >>>>>>>>>>> the unwanted mixing products. If that's all correct, as I believe >>>>>>>>>>> it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>> diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>> like a pentode. Or even a single diode. All do some flavor of >>>>>>>>> multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>> resembles other multiplier-type things once you lowpass filter the >>>>>>>>> output. That's a "synchronous detector", which we usually do in an >>>>>>>>> FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>> signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean
    something which 'sniffs' a small amount of a signal for testing
    purposes. Like a few turns of wire around a transmission line will >>>>>>> 'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>> manner a sampling oscilloscope works. That's what threw me. I tend to >>>>>>> interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across >>>>>> with google.

    It's the HP8566B - a very well known lab-grade analyser of the day
    which many RF designers still use. There is a *ton* of service info on >>>>> this model online. However, I have not been able to see a *proper*
    schematic for the "sampler" in the A11A5 board which is where the issue >>>>> is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/
    hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr-
    programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/
    HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B,
    %208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages, will >>>> take some time.
    I presume you have these?
    Took 10 seconds to find with google

    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to >>>> 12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium
    reference)
    Also build a small downmixer so it can see 2.4 GHz too Plenty free
    spectral display programs online for it,
    I wrote my own:
    https://panteltje.nl/panteltje/xpsa/index.html
    it also has an 'harmonic' button to look for the next harmonic when you >>>> select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi..
    The RTL_SDR sticks can even receive GPS signals...
    https://panteltje.nl/pub/run_50_outside_2728000.gif uses this guys
    software<;
    http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr-
    domain.html

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use >>>> for my Raspberry)
    and there are several audio programs with spectrum display

    There are so many possibilities...

    HP always put the theory notes in the HP Journal, so I'd suggest
    searching there for the HP8566B, in the issues around when the
    instrument was first introduced.

    This analyser is well over 30 years old, so whatever's gone wrong is most
    likely age-related and wouldn't have come to light for many years.
    Fortunately there's a lot of info out there - *if* you can find it!

    On the lack of a schematic, I did dig into how it worked many years
    ago, and as I recall it was based of some fancy abuse of a slotted rectangular waveguide which supported various orthogonal modes - this
    cannot be described by any lumped-parameter circuit.

    Try this:

    US4647795A, Travelling wave sampler, Agoston Agoston, Beaverton, Oreg. Tektronix, Inc., Beaverton, Oreg. granted 3 March 1987.

    .<https://patents.google.com/patent/US4647795A>

    It does have schematics, in a manner of speaking.

    Joe Gwinn

    If it's Agoston's, it's a genuine time-domain short-pulse sampler,
    not an attenuator pick-off.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to piglet on Tue Jul 30 23:39:07 2024
    On 7/30/24 23:27, piglet wrote:
    Jeroen Belleman <jeroen@nospam.please> wrote:
    On 7/30/24 19:46, Joe Gwinn wrote:
    On Tue, 30 Jul 2024 15:13:47 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 11:01:17 -0400, Joe Gwinn wrote:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje <alien@comet.invalid> >>>>> wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened >>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened >>>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje
    <alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>>>> AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>>>> out. The signal from the LHS is passed through a very fast diode >>>>>>>>>>>>> which generates harmonics from that fundamental. The signal from >>>>>>>>>>>>> the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>>>>>> the necessary output signal which is then filtered to get rid of >>>>>>>>>>>>> the unwanted mixing products. If that's all correct, as I believe >>>>>>>>>>>>> it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>>>> diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>>>> like a pentode. Or even a single diode. All do some flavor of >>>>>>>>>>> multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>>>> resembles other multiplier-type things once you lowpass filter the >>>>>>>>>>> output. That's a "synchronous detector", which we usually do in an >>>>>>>>>>> FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>>>> signals.

    A the word 'mixer' in RF is not the same as a multiplier,, >>>>>>>>>> Multipliers are like harmonic generating stages say you have a 1 >>>>>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>>>> something which 'sniffs' a small amount of a signal for testing >>>>>>>>> purposes. Like a few turns of wire around a transmission line will >>>>>>>>> 'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>>>> manner a sampling oscilloscope works. That's what threw me. I tend to >>>>>>>>> interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across >>>>>>>> with google.

    It's the HP8566B - a very well known lab-grade analyser of the day >>>>>>> which many RF designers still use. There is a *ton* of service info on >>>>>>> this model online. However, I have not been able to see a *proper* >>>>>>> schematic for the "sampler" in the A11A5 board which is where the issue >>>>>>> is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/
    hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr-
    programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/
    HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B,
    %208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages, will >>>>>> take some time.
    I presume you have these?
    Took 10 seconds to find with google

    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to >>>>>> 12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium
    reference)
    Also build a small downmixer so it can see 2.4 GHz too Plenty free >>>>>> spectral display programs online for it,
    I wrote my own:
    https://panteltje.nl/panteltje/xpsa/index.html
    it also has an 'harmonic' button to look for the next harmonic when you >>>>>> select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi..
    The RTL_SDR sticks can even receive GPS signals...
    https://panteltje.nl/pub/run_50_outside_2728000.gif uses this guys >>>>>> software<;
    http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr- >>>> domain.html

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use >>>>>> for my Raspberry)
    and there are several audio programs with spectrum display

    There are so many possibilities...

    HP always put the theory notes in the HP Journal, so I'd suggest
    searching there for the HP8566B, in the issues around when the
    instrument was first introduced.

    This analyser is well over 30 years old, so whatever's gone wrong is most >>>> likely age-related and wouldn't have come to light for many years.
    Fortunately there's a lot of info out there - *if* you can find it!

    On the lack of a schematic, I did dig into how it worked many years
    ago, and as I recall it was based of some fancy abuse of a slotted
    rectangular waveguide which supported various orthogonal modes - this
    cannot be described by any lumped-parameter circuit.

    Try this:

    US4647795A, Travelling wave sampler, Agoston Agoston, Beaverton, Oreg.
    Tektronix, Inc., Beaverton, Oreg. granted 3 March 1987.

    .<https://patents.google.com/patent/US4647795A>

    It does have schematics, in a manner of speaking.

    Joe Gwinn

    If it's Agoston's, it's a genuine time-domain short-pulse sampler,
    not an attenuator pick-off.

    Jeroen Belleman


    Doesn’t this predate Agoston’s work?



    Looks like it does, indeed.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Cursitor Doom on Tue Jul 30 21:58:44 2024
    On Tue, 30 Jul 2024 21:08:34 -0000 (UTC), Cursitor Doom wrote:

    On Tue, 30 Jul 2024 13:15:59 -0700, john larkin wrote:

    On Tue, 30 Jul 2024 19:21:28 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 10:39:37 -0700, john larkin wrote:

    On Tue, 30 Jul 2024 08:58:35 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. AFAICT, >>>>>>>>>there's are two signals into this thing and one signal out. The >>>>>>>>>signal from the LHS is passed through a very fast diode which >>>>>>>>>generates harmonics from that fundamental. The signal from the >>>>>>>>>RHS is unmodified and mixed with the desired harmonic to give the >>>>>>>>>necessary output signal which is then filtered to get rid of the >>>>>>>>>unwanted mixing products. If that's all correct, as I believe it >>>>>>>>>is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>like a pentode. Or even a single diode. All do some flavor of >>>>>>>multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1
    MHz distorted sine wave and then a second stage tuned at 3 MHz,..
    turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>something which 'sniffs' a small amount of a signal for testing >>>>>purposes. Like a few turns of wire around a transmission line will >>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>manner a sampling oscilloscope works. That's what threw me. I tend to >>>>>interpret things very literally. :(

    The sampler in the SA schematic is precisely the sort of sampler used
    in a sampling scope. It contains a step-recovery diode impulse
    generator and no doubt some sampling diodes.

    How can you say that when you haven't seen the schematic? If you've
    been able to find it online somewhere then kindly post a link to it
    here.

    You posted an excerpt from the HP manual where the sampler is
    described.

    But you said:
    "The sampler in the SA schematic is precisely the sort of sampler used
    in a sampling scope."

    So you must have had sight of the schematic. I'd really appreciate it if
    you could post a link to it.

    Also, you said the SRD was acting as an "impulse generator" when I assumed
    it was simply generating harmonics to boost the M/N loop output up in
    order to mix with the output of the YTO.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From piglet@21:1/5 to Jeroen Belleman on Tue Jul 30 21:27:41 2024
    Jeroen Belleman <jeroen@nospam.please> wrote:
    On 7/30/24 19:46, Joe Gwinn wrote:
    On Tue, 30 Jul 2024 15:13:47 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 11:01:17 -0400, Joe Gwinn wrote:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened >>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje
    <alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>>> AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>>> out. The signal from the LHS is passed through a very fast diode >>>>>>>>>>>> which generates harmonics from that fundamental. The signal from >>>>>>>>>>>> the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>>>>> the necessary output signal which is then filtered to get rid of >>>>>>>>>>>> the unwanted mixing products. If that's all correct, as I believe >>>>>>>>>>>> it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>>> diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>>> like a pentode. Or even a single diode. All do some flavor of >>>>>>>>>> multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>>> resembles other multiplier-type things once you lowpass filter the >>>>>>>>>> output. That's a "synchronous detector", which we usually do in an >>>>>>>>>> FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>>> signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>>> something which 'sniffs' a small amount of a signal for testing >>>>>>>> purposes. Like a few turns of wire around a transmission line will >>>>>>>> 'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>>> manner a sampling oscilloscope works. That's what threw me. I tend to >>>>>>>> interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across >>>>>>> with google.

    It's the HP8566B - a very well known lab-grade analyser of the day >>>>>> which many RF designers still use. There is a *ton* of service info on >>>>>> this model online. However, I have not been able to see a *proper* >>>>>> schematic for the "sampler" in the A11A5 board which is where the issue >>>>>> is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/
    hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr-
    programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/
    HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B,
    %208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages, will >>>>> take some time.
    I presume you have these?
    Took 10 seconds to find with google

    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to >>>>> 12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium
    reference)
    Also build a small downmixer so it can see 2.4 GHz too Plenty free
    spectral display programs online for it,
    I wrote my own:
    https://panteltje.nl/panteltje/xpsa/index.html
    it also has an 'harmonic' button to look for the next harmonic when you >>>>> select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi..
    The RTL_SDR sticks can even receive GPS signals...
    https://panteltje.nl/pub/run_50_outside_2728000.gif uses this guys
    software<;
    http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr-
    domain.html

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use >>>>> for my Raspberry)
    and there are several audio programs with spectrum display

    There are so many possibilities...

    HP always put the theory notes in the HP Journal, so I'd suggest
    searching there for the HP8566B, in the issues around when the
    instrument was first introduced.

    This analyser is well over 30 years old, so whatever's gone wrong is most >>> likely age-related and wouldn't have come to light for many years.
    Fortunately there's a lot of info out there - *if* you can find it!

    On the lack of a schematic, I did dig into how it worked many years
    ago, and as I recall it was based of some fancy abuse of a slotted
    rectangular waveguide which supported various orthogonal modes - this
    cannot be described by any lumped-parameter circuit.

    Try this:

    US4647795A, Travelling wave sampler, Agoston Agoston, Beaverton, Oreg.
    Tektronix, Inc., Beaverton, Oreg. granted 3 March 1987.

    .<https://patents.google.com/patent/US4647795A>

    It does have schematics, in a manner of speaking.

    Joe Gwinn

    If it's Agoston's, it's a genuine time-domain short-pulse sampler,
    not an attenuator pick-off.

    Jeroen Belleman


    Doesn’t this predate Agoston’s work?


    --
    piglet

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to All on Tue Jul 30 18:13:36 2024
    On Tue, 30 Jul 2024 13:31:20 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Tue, 30 Jul 2024 13:46:06 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 30 Jul 2024 15:13:47 -0000 (UTC), Cursitor Doom >><cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 11:01:17 -0400, Joe Gwinn wrote:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened >>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>><v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened >>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>>>out. The signal from the LHS is passed through a very fast diode >>>>>>>>>>>>which generates harmonics from that fundamental. The signal from >>>>>>>>>>>>the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>>>>>the necessary output signal which is then filtered to get rid of >>>>>>>>>>>>the unwanted mixing products. If that's all correct, as I believe >>>>>>>>>>>>it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>>>like a pentode. Or even a single diode. All do some flavor of >>>>>>>>>>multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>>>something which 'sniffs' a small amount of a signal for testing >>>>>>>>purposes. Like a few turns of wire around a transmission line will >>>>>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>>>manner a sampling oscilloscope works. That's what threw me. I tend to >>>>>>>>interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across >>>>>>> with google.

    It's the HP8566B - a very well known lab-grade analyser of the day >>>>>>which many RF designers still use. There is a *ton* of service info on >>>>>>this model online. However, I have not been able to see a *proper* >>>>>>schematic for the "sampler" in the A11A5 board which is where the issue >>>>>>is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    < https://elektrotanya.com/> >>>hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- >>>programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    < https://xdevs.com/doc/HP_Agilent_Keysight/> >>>HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    < https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, >>>%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf>
    also has some circuits I will have a look at the hundreds of pages, will >>>>>take some time.
    I presume you have these?
    Took 10 seconds to find with google

    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    < https://www.ebay.com/p/22032165355?iid=335019807057>
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to >>>>>12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium >>>>>reference)
    Also build a small downmixer so it can see 2.4 GHz too Plenty free >>>>>spectral display programs online for it,
    I wrote my own:
    <https://panteltje.nl/panteltje/xpsa/index.html>
    it also has an 'harmonic' button to look for the next harmonic when you >>>>>select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi..
    The RTL_SDR sticks can even receive GPS signals...
    <https://panteltje.nl/pub/run_50_outside_2728000.gif > uses this guys >>>>> software<;
    <http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr-domain.html>

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use >>>>>for my Raspberry)
    and there are several audio programs with spectrum display

    There are so many possibilities...

    HP always put the theory notes in the HP Journal, so I'd suggest
    searching there for the HP8566B, in the issues around when the
    instrument was first introduced.

    This analyser is well over 30 years old, so whatever's gone wrong is most >>>likely age-related and wouldn't have come to light for many years. >>>Fortunately there's a lot of info out there - *if* you can find it!

    On the lack of a schematic, I did dig into how it worked many years
    ago, and as I recall it was based of some fancy abuse of a slotted >>rectangular waveguide which supported various orthogonal modes - this >>cannot be described by any lumped-parameter circuit.

    Try this:

    US4647795A, Travelling wave sampler, Agoston Agoston, Beaverton, Oreg. >>Tektronix, Inc., Beaverton, Oreg. granted 3 March 1987.

    .<https://patents.google.com/patent/US4647795A>

    It does have schematics, in a manner of speaking.

    Joe Gwinn

    I have an old HP sampling plugin that uses a machined block slotline >structure. 3 GHz bandwidth as I recall.

    <https://www.dropbox.com/scl/fo/3h4fvsfdh2youfd4kuolk/AIapB4g1x0BYRNXRIrAsrO8?rlkey=q5v7llkkk6yagr2w7h4c4kq8k&dl=0>

    Agoston has a patent for a similar metal-block slotline sampler, but
    as far as I know Tek never manufactured it. The SD-series samplers
    were hybrids.

    <https://www.dropbox.com/scl/fo/dnejszdktyc70se6frcdo/AM4vWFFsXPPF4Tw2ZeEm6m8?rlkey=xm82mhqn5mnrlv3l9j0pebj29&dl=0>

    I recall these pictures. I was wondering if HP copied the general
    approach if not the patented design. Or licence it.

    Jeroen correctly commented that "If it's Agoston's, it's a genuine
    time-domain short-pulse sampler, not an attenuator pick-off."

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to cd999666@notformail.com on Tue Jul 30 17:34:51 2024
    On Tue, 30 Jul 2024 21:58:44 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 21:08:34 -0000 (UTC), Cursitor Doom wrote:

    On Tue, 30 Jul 2024 13:15:59 -0700, john larkin wrote:

    On Tue, 30 Jul 2024 19:21:28 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 10:39:37 -0700, john larkin wrote:

    On Tue, 30 Jul 2024 08:58:35 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. AFAICT, >>>>>>>>>>there's are two signals into this thing and one signal out. The >>>>>>>>>>signal from the LHS is passed through a very fast diode which >>>>>>>>>>generates harmonics from that fundamental. The signal from the >>>>>>>>>>RHS is unmodified and mixed with the desired harmonic to give the >>>>>>>>>>necessary output signal which is then filtered to get rid of the >>>>>>>>>>unwanted mixing products. If that's all correct, as I believe it >>>>>>>>>>is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>like a pentode. Or even a single diode. All do some flavor of >>>>>>>>multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>something which 'sniffs' a small amount of a signal for testing >>>>>>purposes. Like a few turns of wire around a transmission line will >>>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>manner a sampling oscilloscope works. That's what threw me. I tend to >>>>>>interpret things very literally. :(

    The sampler in the SA schematic is precisely the sort of sampler used >>>>> in a sampling scope. It contains a step-recovery diode impulse
    generator and no doubt some sampling diodes.

    How can you say that when you haven't seen the schematic? If you've >>>>been able to find it online somewhere then kindly post a link to it >>>>here.

    You posted an excerpt from the HP manual where the sampler is
    described.

    But you said:
    "The sampler in the SA schematic is precisely the sort of sampler used
    in a sampling scope."

    So you must have had sight of the schematic. I'd really appreciate it if
    you could post a link to it.

    No, all I saw was the description.


    Also, you said the SRD was acting as an "impulse generator" when I assumed
    it was simply generating harmonics to boost the M/N loop output up in
    order to mix with the output of the YTO.

    They are really the same thing. An impulse train is a harmonic comb.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Tue Jul 30 17:31:50 2024
    On Tue, 30 Jul 2024 18:13:36 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 30 Jul 2024 13:31:20 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Tue, 30 Jul 2024 13:46:06 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 30 Jul 2024 15:13:47 -0000 (UTC), Cursitor Doom >>><cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 11:01:17 -0400, Joe Gwinn wrote:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje <alien@comet.invalid> >>>>> wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened >>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>><v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened >>>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>>>>out. The signal from the LHS is passed through a very fast diode >>>>>>>>>>>>>which generates harmonics from that fundamental. The signal from >>>>>>>>>>>>>the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>>>>>>the necessary output signal which is then filtered to get rid of >>>>>>>>>>>>>the unwanted mixing products. If that's all correct, as I believe >>>>>>>>>>>>>it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>>>>like a pentode. Or even a single diode. All do some flavor of >>>>>>>>>>>multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,, >>>>>>>>>> Multipliers are like harmonic generating stages say you have a 1 >>>>>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>>>>something which 'sniffs' a small amount of a signal for testing >>>>>>>>>purposes. Like a few turns of wire around a transmission line will >>>>>>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>>>>manner a sampling oscilloscope works. That's what threw me. I tend to >>>>>>>>>interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across >>>>>>>> with google.

    It's the HP8566B - a very well known lab-grade analyser of the day >>>>>>>which many RF designers still use. There is a *ton* of service info on >>>>>>>this model online. However, I have not been able to see a *proper* >>>>>>>schematic for the "sampler" in the A11A5 board which is where the issue >>>>>>>is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    < https://elektrotanya.com/> >>>>hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- >>>>programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    < https://xdevs.com/doc/HP_Agilent_Keysight/> >>>>HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    < https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, >>>>%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf>
    also has some circuits I will have a look at the hundreds of pages, will >>>>>>take some time.
    I presume you have these?
    Took 10 seconds to find with google

    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    < https://www.ebay.com/p/22032165355?iid=335019807057>
    I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to >>>>>>12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium >>>>>>reference)
    Also build a small downmixer so it can see 2.4 GHz too Plenty free >>>>>>spectral display programs online for it,
    I wrote my own:
    <https://panteltje.nl/panteltje/xpsa/index.html>
    it also has an 'harmonic' button to look for the next harmonic when you >>>>>>select a carrier...
    The latest version has some more stuff and runs on Raspberry Pi.. >>>>>>The RTL_SDR sticks can even receive GPS signals...
    <https://panteltje.nl/pub/run_50_outside_2728000.gif > uses this guys >>>>>> software<;
    <http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr-domain.html>

    For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use >>>>>>for my Raspberry)
    and there are several audio programs with spectrum display

    There are so many possibilities...

    HP always put the theory notes in the HP Journal, so I'd suggest
    searching there for the HP8566B, in the issues around when the
    instrument was first introduced.

    This analyser is well over 30 years old, so whatever's gone wrong is most >>>>likely age-related and wouldn't have come to light for many years. >>>>Fortunately there's a lot of info out there - *if* you can find it!

    On the lack of a schematic, I did dig into how it worked many years
    ago, and as I recall it was based of some fancy abuse of a slotted >>>rectangular waveguide which supported various orthogonal modes - this >>>cannot be described by any lumped-parameter circuit.

    Try this:

    US4647795A, Travelling wave sampler, Agoston Agoston, Beaverton, Oreg. >>>Tektronix, Inc., Beaverton, Oreg. granted 3 March 1987.

    .<https://patents.google.com/patent/US4647795A>

    It does have schematics, in a manner of speaking.

    Joe Gwinn

    I have an old HP sampling plugin that uses a machined block slotline >>structure. 3 GHz bandwidth as I recall.
    <https://www.dropbox.com/scl/fo/3h4fvsfdh2youfd4kuolk/AIapB4g1x0BYRNXRIrAsrO8?rlkey=q5v7llkkk6yagr2w7h4c4kq8k&dl=0>

    Agoston has a patent for a similar metal-block slotline sampler, but
    as far as I know Tek never manufactured it. The SD-series samplers
    were hybrids.
    <https://www.dropbox.com/scl/fo/dnejszdktyc70se6frcdo/AM4vWFFsXPPF4Tw2ZeEm6m8?rlkey=xm82mhqn5mnrlv3l9j0pebj29&dl=0>

    I recall these pictures. I was wondering if HP copied the general
    approach if not the patented design. Or licence it.

    Jeroen correctly commented that "If it's Agoston's, it's a genuine >time-domain short-pulse sampler, not an attenuator pick-off."

    Joe Gwinn

    I recall that the founders of Tek and HP met and agreed to
    cross-license their patents.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to Doom on Wed Jul 31 10:54:58 2024
    On a sunny day (Tue, 30 Jul 2024 15:11:35 -0000 (UTC)) it happened Cursitor Doom <cd999666@notformail.com> wrote in <v8avr7$13368$1@dont-email.me>:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
    larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it happened >>>>>>>>Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>>out. The signal from the LHS is passed through a very fast diode >>>>>>>>>which generates harmonics from that fundamental. The signal from >>>>>>>>>the RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>>the necessary output signal which is then filtered to get rid of >>>>>>>>>the unwanted mixing products. If that's all correct, as I believe >>>>>>>>>it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant diode >>>>>>>thing or a Gilbert cell type circuit. Or a 2-quadrant thing like a >>>>>>>pentode. Or even a single diode. All do some flavor of multiplying. >>>>>>>
    Some mixers inherently multiply a signal by a square wave, which >>>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 MHz >>>>>> distorted sine wave and then a second stage tuned at 3 MHz,.. turned >>>>>> to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>something which 'sniffs' a small amount of a signal for testing >>>>>purposes. Like a few turns of wire around a transmission line will >>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>manner a sampling oscilloscope works. That's what threw me. I tend to >>>>>interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came across
    with google.

    It's the HP8566B - a very well known lab-grade analyser of the day which >>>many RF designers still use. There is a *ton* of service info on this >>>model online. However, I have not been able to see a *proper* schematic >>>for the "sampler" in the A11A5 board which is where the issue is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/ >hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- >programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/ >HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, >%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages, will
    take some time.
    I presume you have these?
    Took 10 seconds to find with google

    Yes, I have all of those and more. I think altogether there are 7 very
    large manuals for this analyser. However, I've not been able to find a
    single actual schematic which gives component level detail of what they
    call the "sampler" - and that's unusual, as they've given a great deal of >attention to providing very full service details in all other respects.

    Will read some of it and let you know what I come up with ..

    OK have flipped through all circuit diagrams in the thing.

    It looks to me like a heterodyne down converter followed by a narrow filter IF stage
    tuned over the whole frequency range.
    No sampling on the input signal at all.
    Just a RF mixer.
    PLLs in the tuned oscillator that are used to scan the band.

    Like an old AM shortwave radio where you turn the big tuning knob really fast mechanically to see the amplitude of each station
    on the cats eye as you tune over the whole receive spectrum.
    spectrum width set by the 450 kHz or so IF filter stages in those radio days....
    To get the IF narrow enough I did notice some crystal filter?, multi stage RC filters?
    Scanning the band takes time that way... horizontal deflection scope, amplitude on vertical deflection scope..
    Does it have a long persistence screen?
    That way you can point at any small section of the input like long wave / medium wave / shortwave in the old radios.
    Also because I do not see any Fourier transform / computah / computation..

    That thing is from 1987? enough computah power back then for Fourier transform?

    I could be wrong though, more than a 1000 pages read in... lemme see... an hour.
    Need to sleep on it and look again.
    Rest is just scope trace drive and power supplies..
    Its all so easy:
    https://panteltje.nl/panteltje/scope_tv/index.html
    HP should have added a teefee mode, but alas, analog teefee is dead in most of the world these days.

    This is more fun:
    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057

    Use a Raspberry Pi or a PC ..

    I remember when I build a frequency counter with nixy tubes and TTL and 100 kHz crystal
    took it to work (tube days) it blew the guys away..
    Then demoed it at the local ham group connected to the local oscillator of a shortwave receiver
    Explained 'subtract the IF frequency from the indicated frequency to get the real frequency'
    Most radios have that now with nice LCD screens and PLL local oscillators.... Or now even direct sampling
    like that SDR_RTL stuff.


    I personally would dump the HP thing.. or maybe donate it to some museum..

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Wed Jul 31 07:24:04 2024
    On Tue, 30 Jul 2024 17:34:51 -0700, john larkin wrote:

    On Tue, 30 Jul 2024 21:58:44 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 21:08:34 -0000 (UTC), Cursitor Doom wrote:

    On Tue, 30 Jul 2024 13:15:59 -0700, john larkin wrote:

    On Tue, 30 Jul 2024 19:21:28 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 10:39:37 -0700, john larkin wrote:

    On Tue, 30 Jul 2024 08:58:35 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it >>>>>>>>>>happened Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>>AFAICT,
    there's are two signals into this thing and one signal out. The >>>>>>>>>>>signal from the LHS is passed through a very fast diode which >>>>>>>>>>>generates harmonics from that fundamental. The signal from the >>>>>>>>>>>RHS is unmodified and mixed with the desired harmonic to give >>>>>>>>>>>the necessary output signal which is then filtered to get rid >>>>>>>>>>>of the unwanted mixing products. If that's all correct, as I >>>>>>>>>>>believe it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>>like a pentode. Or even a single diode. All do some flavor of >>>>>>>>>multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>>resembles other multiplier-type things once you lowpass filter >>>>>>>>>the output. That's a "synchronous detector", which we usually do >>>>>>>>>in an FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>>something which 'sniffs' a small amount of a signal for testing >>>>>>>purposes. Like a few turns of wire around a transmission line will >>>>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>>manner a sampling oscilloscope works. That's what threw me. I tend >>>>>>>to interpret things very literally. :(

    The sampler in the SA schematic is precisely the sort of sampler
    used in a sampling scope. It contains a step-recovery diode impulse >>>>>> generator and no doubt some sampling diodes.

    How can you say that when you haven't seen the schematic? If you've >>>>>been able to find it online somewhere then kindly post a link to it >>>>>here.

    You posted an excerpt from the HP manual where the sampler is
    described.

    But you said:
    "The sampler in the SA schematic is precisely the sort of sampler used
    in a sampling scope."

    So you must have had sight of the schematic. I'd really appreciate it
    if you could post a link to it.

    No, all I saw was the description.


    Also, you said the SRD was acting as an "impulse generator" when I
    assumed it was simply generating harmonics to boost the M/N loop output
    up in order to mix with the output of the YTO.

    They are really the same thing. An impulse train is a harmonic comb.

    So we're just getting hung up on definitions? Fine, let's leave it at
    that.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Jan Panteltje on Wed Jul 31 14:46:52 2024
    On Wed, 31 Jul 2024 10:54:58 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 15:11:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in <v8avr7$13368$1@dont-email.me>:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it >>>>>>>>>happened Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>out. The signal from the LHS is passed through a very fast diode >>>>>>>>>>which generates harmonics from that fundamental. The signal from >>>>>>>>>>the RHS is unmodified and mixed with the desired harmonic to >>>>>>>>>>give the necessary output signal which is then filtered to get >>>>>>>>>>rid of the unwanted mixing products. If that's all correct, as I >>>>>>>>>>believe it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>like a pentode. Or even a single diode. All do some flavor of >>>>>>>>multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>something which 'sniffs' a small amount of a signal for testing >>>>>>purposes. Like a few turns of wire around a transmission line will >>>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>manner a sampling oscilloscope works. That's what threw me. I tend >>>>>>to interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came
    across with google.

    It's the HP8566B - a very well known lab-grade analyser of the day >>>>which many RF designers still use. There is a *ton* of service info on >>>>this model online. However, I have not been able to see a *proper* >>>>schematic for the "sampler" in the A11A5 board which is where the
    issue is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/ >>hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- >>programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/ >>HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, >>%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages,
    will take some time.
    I presume you have these?
    Took 10 seconds to find with google

    Yes, I have all of those and more. I think altogether there are 7 very >>large manuals for this analyser. However, I've not been able to find a >>single actual schematic which gives component level detail of what they >>call the "sampler" - and that's unusual, as they've given a great deal
    of attention to providing very full service details in all other
    respects.

    Will read some of it and let you know what I come up with ..

    OK have flipped through all circuit diagrams in the thing.

    It looks to me like a heterodyne down converter followed by a narrow
    filter IF stage tuned over the whole frequency range.
    No sampling on the input signal at all.
    Just a RF mixer.
    PLLs in the tuned oscillator that are used to scan the band.

    Like an old AM shortwave radio where you turn the big tuning knob really
    fast mechanically to see the amplitude of each station on the cats eye
    as you tune over the whole receive spectrum.
    spectrum width set by the 450 kHz or so IF filter stages in those radio days....
    To get the IF narrow enough I did notice some crystal filter?, multi
    stage RC filters?
    Scanning the band takes time that way... horizontal deflection scope, amplitude on vertical deflection scope..
    Does it have a long persistence screen?
    That way you can point at any small section of the input like long wave
    / medium wave / shortwave in the old radios.
    Also because I do not see any Fourier transform / computah /
    computation..

    That thing is from 1987? enough computah power back then for Fourier transform?

    I could be wrong though, more than a 1000 pages read in... lemme see...
    an hour.
    Need to sleep on it and look again.
    Rest is just scope trace drive and power supplies..
    Its all so easy:
    https://panteltje.nl/panteltje/scope_tv/index.html
    HP should have added a teefee mode, but alas, analog teefee is dead in
    most of the world these days.

    This is more fun:
    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057

    Use a Raspberry Pi or a PC ..

    I remember when I build a frequency counter with nixy tubes and TTL and
    100 kHz crystal took it to work (tube days) it blew the guys away..
    Then demoed it at the local ham group connected to the local oscillator
    of a shortwave receiver Explained 'subtract the IF frequency from the indicated frequency to get the real frequency'
    Most radios have that now with nice LCD screens and PLL local
    oscillators.... Or now even direct sampling like that SDR_RTL stuff.


    I personally would dump the HP thing.. or maybe donate it to some
    museum..

    Haha! No, neither of those things are going to happen, Jan. I'm still
    suffering from PTSD at having to toss a Tek 555 into a dumpster 20 years
    ago.
    Plus...... I've ordered *another* HP boat anchor to assist me to fix this
    one! You can never have too many boat anchors (although of course, I
    have). :)

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to cd999666@notformail.com on Wed Jul 31 08:41:02 2024
    On Wed, 31 Jul 2024 14:46:52 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Wed, 31 Jul 2024 10:54:58 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 15:11:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8avr7$13368$1@dont-email.me>:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened >>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it >>>>>>>>>>happened Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>>out. The signal from the LHS is passed through a very fast diode >>>>>>>>>>>which generates harmonics from that fundamental. The signal from >>>>>>>>>>>the RHS is unmodified and mixed with the desired harmonic to >>>>>>>>>>>give the necessary output signal which is then filtered to get >>>>>>>>>>>rid of the unwanted mixing products. If that's all correct, as I >>>>>>>>>>>believe it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>>like a pentode. Or even a single diode. All do some flavor of >>>>>>>>>multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>>something which 'sniffs' a small amount of a signal for testing >>>>>>>purposes. Like a few turns of wire around a transmission line will >>>>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>>manner a sampling oscilloscope works. That's what threw me. I tend >>>>>>>to interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came
    across with google.

    It's the HP8566B - a very well known lab-grade analyser of the day >>>>>which many RF designers still use. There is a *ton* of service info on >>>>>this model online. However, I have not been able to see a *proper* >>>>>schematic for the "sampler" in the A11A5 board which is where the >>>>>issue is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/ >>>hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- >>>programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/ >>>HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, >>>%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages,
    will take some time.
    I presume you have these?
    Took 10 seconds to find with google

    Yes, I have all of those and more. I think altogether there are 7 very >>>large manuals for this analyser. However, I've not been able to find a >>>single actual schematic which gives component level detail of what they >>>call the "sampler" - and that's unusual, as they've given a great deal
    of attention to providing very full service details in all other >>>respects.

    Will read some of it and let you know what I come up with ..

    OK have flipped through all circuit diagrams in the thing.

    It looks to me like a heterodyne down converter followed by a narrow
    filter IF stage tuned over the whole frequency range.
    No sampling on the input signal at all.
    Just a RF mixer.
    PLLs in the tuned oscillator that are used to scan the band.

    Like an old AM shortwave radio where you turn the big tuning knob really
    fast mechanically to see the amplitude of each station on the cats eye
    as you tune over the whole receive spectrum.
    spectrum width set by the 450 kHz or so IF filter stages in those radio
    days....
    To get the IF narrow enough I did notice some crystal filter?, multi
    stage RC filters?
    Scanning the band takes time that way... horizontal deflection scope,
    amplitude on vertical deflection scope..
    Does it have a long persistence screen?
    That way you can point at any small section of the input like long wave
    / medium wave / shortwave in the old radios.
    Also because I do not see any Fourier transform / computah /
    computation..

    That thing is from 1987? enough computah power back then for Fourier
    transform?

    I could be wrong though, more than a 1000 pages read in... lemme see...
    an hour.
    Need to sleep on it and look again.
    Rest is just scope trace drive and power supplies..
    Its all so easy:
    https://panteltje.nl/panteltje/scope_tv/index.html
    HP should have added a teefee mode, but alas, analog teefee is dead in
    most of the world these days.

    This is more fun:
    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057

    Use a Raspberry Pi or a PC ..

    I remember when I build a frequency counter with nixy tubes and TTL and
    100 kHz crystal took it to work (tube days) it blew the guys away..
    Then demoed it at the local ham group connected to the local oscillator
    of a shortwave receiver Explained 'subtract the IF frequency from the
    indicated frequency to get the real frequency'
    Most radios have that now with nice LCD screens and PLL local
    oscillators.... Or now even direct sampling like that SDR_RTL stuff.


    I personally would dump the HP thing.. or maybe donate it to some
    museum..

    Haha! No, neither of those things are going to happen, Jan. I'm still >suffering from PTSD at having to toss a Tek 555 into a dumpster 20 years
    ago.
    Plus...... I've ordered *another* HP boat anchor to assist me to fix this >one! You can never have too many boat anchors (although of course, I
    have). :)

    Those old monsters were big, heavy, and immensely complex. Not so
    reliable.

    Nowadays you can get a nice color digital SA with tracking generator
    for around $1300 from Amazon. The little handheld toys start around
    $60.

    I think I'll order one for my new lab. Does anyone have suggestions?
    There's a 1.5 GHz Rigol for $1300 and a 3.2g Siglent for $2600.

    One key point will be front-end preselection/image rejection. I've
    found that even the classic HPs had terrible spruious spikes, at
    harmonics of the input frequency. Tek made one SA plugin that had *no*
    image rejection. You had to figure it out yourself.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Wed Jul 31 19:02:43 2024
    On Wed, 31 Jul 2024 08:41:02 -0700, john larkin wrote:

    On Wed, 31 Jul 2024 14:46:52 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Wed, 31 Jul 2024 10:54:58 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 15:11:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8avr7$13368$1@dont-email.me>:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened >>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened >>>>>>>>> john larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it >>>>>>>>>>>happened Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>>>out. The signal from the LHS is passed through a very fast >>>>>>>>>>>>diode which generates harmonics from that fundamental. The >>>>>>>>>>>>signal from the RHS is unmodified and mixed with the desired >>>>>>>>>>>>harmonic to give the necessary output signal which is then >>>>>>>>>>>>filtered to get rid of the unwanted mixing products. If that's >>>>>>>>>>>>all correct, as I believe it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant >>>>>>>>>>thing like a pentode. Or even a single diode. All do some flavor >>>>>>>>>>of multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>>>resembles other multiplier-type things once you lowpass filter >>>>>>>>>>the output. That's a "synchronous detector", which we usually do >>>>>>>>>>in an FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>>>> MHz distorted sine wave and then a second stage tuned at 3
    MHz,..
    turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>>>something which 'sniffs' a small amount of a signal for testing >>>>>>>>purposes. Like a few turns of wire around a transmission line will >>>>>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>>>manner a sampling oscilloscope works. That's what threw me. I tend >>>>>>>>to interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came
    across with google.

    It's the HP8566B - a very well known lab-grade analyser of the day >>>>>>which many RF designers still use. There is a *ton* of service info >>>>>>on this model online. However, I have not been able to see a >>>>>>*proper* schematic for the "sampler" in the A11A5 board which is >>>>>>where the issue is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/ >>>>hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- >>>>programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/ >>>>HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, >>>>%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages,
    will take some time.
    I presume you have these?
    Took 10 seconds to find with google

    Yes, I have all of those and more. I think altogether there are 7 very >>>>large manuals for this analyser. However, I've not been able to find a >>>>single actual schematic which gives component level detail of what
    they call the "sampler" - and that's unusual, as they've given a great >>>>deal of attention to providing very full service details in all other >>>>respects.

    Will read some of it and let you know what I come up with ..

    OK have flipped through all circuit diagrams in the thing.

    It looks to me like a heterodyne down converter followed by a narrow
    filter IF stage tuned over the whole frequency range.
    No sampling on the input signal at all.
    Just a RF mixer.
    PLLs in the tuned oscillator that are used to scan the band.

    Like an old AM shortwave radio where you turn the big tuning knob
    really fast mechanically to see the amplitude of each station on the
    cats eye as you tune over the whole receive spectrum.
    spectrum width set by the 450 kHz or so IF filter stages in those
    radio days....
    To get the IF narrow enough I did notice some crystal filter?, multi
    stage RC filters?
    Scanning the band takes time that way... horizontal deflection scope,
    amplitude on vertical deflection scope..
    Does it have a long persistence screen?
    That way you can point at any small section of the input like long
    wave / medium wave / shortwave in the old radios.
    Also because I do not see any Fourier transform / computah /
    computation..

    That thing is from 1987? enough computah power back then for Fourier
    transform?

    I could be wrong though, more than a 1000 pages read in... lemme
    see... an hour.
    Need to sleep on it and look again.
    Rest is just scope trace drive and power supplies..
    Its all so easy:
    https://panteltje.nl/panteltje/scope_tv/index.html
    HP should have added a teefee mode, but alas, analog teefee is dead in
    most of the world these days.

    This is more fun:
    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057

    Use a Raspberry Pi or a PC ..

    I remember when I build a frequency counter with nixy tubes and TTL
    and 100 kHz crystal took it to work (tube days) it blew the guys
    away.. Then demoed it at the local ham group connected to the local
    oscillator of a shortwave receiver Explained 'subtract the IF
    frequency from the indicated frequency to get the real frequency'
    Most radios have that now with nice LCD screens and PLL local
    oscillators.... Or now even direct sampling like that SDR_RTL stuff.


    I personally would dump the HP thing.. or maybe donate it to some
    museum..

    Haha! No, neither of those things are going to happen, Jan. I'm still >>suffering from PTSD at having to toss a Tek 555 into a dumpster 20 years >>ago.
    Plus...... I've ordered *another* HP boat anchor to assist me to fix
    this one! You can never have too many boat anchors (although of course,
    I have). :)

    Those old monsters were big, heavy, and immensely complex. Not so
    reliable.

    True, but when they go wrong, they're repairable without needing to be
    sent off at vast expense to the manufacturer to put right. That is no
    small consideration for the non-commercial users of these things.

    Nowadays you can get a nice color digital SA with tracking generator for around $1300 from Amazon. The little handheld toys start around $60.

    The toys are phenomenal in terms of what they can do for the price, but
    all the key metrics of performance and accuracy aren't satisfied. After
    all, what can you expect for 60 bucks? But undeniably they're *great* for
    kids to learn with.

    I think I'll order one for my new lab. Does anyone have suggestions?
    There's a 1.5 GHz Rigol for $1300 and a 3.2g Siglent for $2600.

    One key point will be front-end preselection/image rejection. I've found
    that even the classic HPs had terrible spruious spikes, at harmonics of
    the input frequency. Tek made one SA plugin that had *no*
    image rejection. You had to figure it out yourself.

    Dunno which model you're referring to there, but I've never had any such problem with the ones I've owned.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to All on Thu Aug 1 05:28:29 2024
    On a sunny day (Wed, 31 Jul 2024 08:41:02 -0700) it happened john larkin <jlarkin_highland_tech> wrote in <i5mkajltsmevfuaii8t6trpseoi6bditvc@4ax.com>:

    Those old monsters were big, heavy, and immensely complex. Not so
    reliable.

    Nowadays you can get a nice color digital SA with tracking generator
    for around $1300 from Amazon. The little handheld toys start around
    $60.

    I think I'll order one for my new lab. Does anyone have suggestions?
    There's a 1.5 GHz Rigol for $1300 and a 3.2g Siglent for $2600.

    One key point will be front-end preselection/image rejection. I've
    found that even the classic HPs had terrible spruious spikes, at
    harmonics of the input frequency. Tek made one SA plugin that had *no*
    image rejection. You had to figure it out yourself.

    Tek had a nice 300 MHz analog one
    I copied the circuit from an electronics magazine (early seventies IIRC) and build
    something similar with it using an East German CRT I got for a few dollies ($$).
    Many years later at Tek I met the man who had published that circuit,
    he had got some headwind for publishing that circuit diagram.
    Donated it when I left for far away...

    It is not just the tool, it is your understanding how to use it and interpret it,
    many dollies ($$) does not help with that.

    But it does perhaps impress customers if you have shelves full of that stuff ;-)
    For me it was just play and curiosity as always.

    In broadcasting I was running around all day with a dual trace analog Tek on a scope card,

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to Doom on Thu Aug 1 05:13:43 2024
    On a sunny day (Wed, 31 Jul 2024 14:46:52 -0000 (UTC)) it happened Cursitor Doom <cd999666@notformail.com> wrote in <v8dios$1kovj$1@dont-email.me>:

    On Wed, 31 Jul 2024 10:54:58 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 15:11:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8avr7$13368$1@dont-email.me>:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened >>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john >>>>>>>> larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it >>>>>>>>>>happened Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>>out. The signal from the LHS is passed through a very fast diode >>>>>>>>>>>which generates harmonics from that fundamental. The signal from >>>>>>>>>>>the RHS is unmodified and mixed with the desired harmonic to >>>>>>>>>>>give the necessary output signal which is then filtered to get >>>>>>>>>>>rid of the unwanted mixing products. If that's all correct, as I >>>>>>>>>>>believe it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing >>>>>>>>>like a pentode. Or even a single diode. All do some flavor of >>>>>>>>>multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>>resembles other multiplier-type things once you lowpass filter the >>>>>>>>>output. That's a "synchronous detector", which we usually do in an >>>>>>>>>FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>>> MHz distorted sine wave and then a second stage tuned at 3 MHz,.. >>>>>>>> turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>>something which 'sniffs' a small amount of a signal for testing >>>>>>>purposes. Like a few turns of wire around a transmission line will >>>>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>>manner a sampling oscilloscope works. That's what threw me. I tend >>>>>>>to interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came
    across with google.

    It's the HP8566B - a very well known lab-grade analyser of the day >>>>>which many RF designers still use. There is a *ton* of service info on >>>>>this model online. However, I have not been able to see a *proper* >>>>>schematic for the "sampler" in the A11A5 board which is where the >>>>>issue is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/ >>>hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- >>>programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/ >>>HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, >>>%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages,
    will take some time.
    I presume you have these?
    Took 10 seconds to find with google

    Yes, I have all of those and more. I think altogether there are 7 very >>>large manuals for this analyser. However, I've not been able to find a >>>single actual schematic which gives component level detail of what they >>>call the "sampler" - and that's unusual, as they've given a great deal
    of attention to providing very full service details in all other >>>respects.

    Will read some of it and let you know what I come up with ..

    OK have flipped through all circuit diagrams in the thing.

    It looks to me like a heterodyne down converter followed by a narrow
    filter IF stage tuned over the whole frequency range.
    No sampling on the input signal at all.
    Just a RF mixer.
    PLLs in the tuned oscillator that are used to scan the band.

    Like an old AM shortwave radio where you turn the big tuning knob really
    fast mechanically to see the amplitude of each station on the cats eye
    as you tune over the whole receive spectrum.
    spectrum width set by the 450 kHz or so IF filter stages in those radio
    days....
    To get the IF narrow enough I did notice some crystal filter?, multi
    stage RC filters?
    Scanning the band takes time that way... horizontal deflection scope,
    amplitude on vertical deflection scope..
    Does it have a long persistence screen?
    That way you can point at any small section of the input like long wave
    / medium wave / shortwave in the old radios.
    Also because I do not see any Fourier transform / computah /
    computation..

    That thing is from 1987? enough computah power back then for Fourier
    transform?

    I could be wrong though, more than a 1000 pages read in... lemme see...
    an hour.
    Need to sleep on it and look again.
    Rest is just scope trace drive and power supplies..
    Its all so easy:
    https://panteltje.nl/panteltje/scope_tv/index.html
    HP should have added a teefee mode, but alas, analog teefee is dead in
    most of the world these days.

    This is more fun:
    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057

    Use a Raspberry Pi or a PC ..

    I remember when I build a frequency counter with nixy tubes and TTL and
    100 kHz crystal took it to work (tube days) it blew the guys away..
    Then demoed it at the local ham group connected to the local oscillator
    of a shortwave receiver Explained 'subtract the IF frequency from the
    indicated frequency to get the real frequency'
    Most radios have that now with nice LCD screens and PLL local
    oscillators.... Or now even direct sampling like that SDR_RTL stuff.


    I personally would dump the HP thing.. or maybe donate it to some
    museum..

    Haha! No, neither of those things are going to happen, Jan. I'm still >suffering from PTSD at having to toss a Tek 555 into a dumpster 20 years
    ago.
    Plus...... I've ordered *another* HP boat anchor to assist me to fix this >one! You can never have too many boat anchors (although of course, I
    have). :)

    Yes, the Tek 555
    https://w140.com/tekwiki/wiki/555
    I likely used that one in those early sixties :-)
    Keep it, good analog scopes are rare...
    I still use my Trio-CS1562 analog scope:
    https://panteltje.nl/pub/APC_UPS_ES700_waveform_25W_edison_bulb_load_IMG_0270.JPG
    it has thousands of hours, was on all day in my TV repair shop..

    But space is always a problem, I have located many times, other countries, donated everything, start new.
    Same for old cars I have driven..
    Citroen 2CV, Peugeot 404 station, Ford Mustang V8, some memories...
    Why did you dump the Tek?
    Those are easy to repair.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Jan Panteltje on Thu Aug 1 08:27:16 2024
    On Thu, 01 Aug 2024 05:13:43 GMT, Jan Panteltje wrote:

    On a sunny day (Wed, 31 Jul 2024 14:46:52 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in <v8dios$1kovj$1@dont-email.me>:

    On Wed, 31 Jul 2024 10:54:58 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 15:11:35 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8avr7$13368$1@dont-email.me>:

    On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8aiaf$10lqo$1@dont-email.me>:

    On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote:

    On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened >>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
    <v8a9vr$v9r2$1@dont-email.me>:

    On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:

    On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened >>>>>>>>> john larkin <jlarkin_highland_tech> wrote in
    <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:

    On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje >>>>>>>>>><alien@comet.invalid> wrote:

    On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it >>>>>>>>>>>happened Cursitor Doom <cd999666@notformail.com> wrote in >>>>>>>>>>><v86dsp$3n74$1@dont-email.me>:


    I still can't see where the 'sampling' bit comes into it. >>>>>>>>>>>>AFAICT, there's are two signals into this thing and one signal >>>>>>>>>>>>out. The signal from the LHS is passed through a very fast >>>>>>>>>>>>diode which generates harmonics from that fundamental. The >>>>>>>>>>>>signal from the RHS is unmodified and mixed with the desired >>>>>>>>>>>>harmonic to give the necessary output signal which is then >>>>>>>>>>>>filtered to get rid of the unwanted mixing products. If that's >>>>>>>>>>>>all correct, as I believe it is,
    where does any *sampling* come into it?

    A 'sampler' is fact a non-linear mixer.

    In the audio world, a "mixer" is a linear summer.

    In RF, a mixer is usually a multiplier, typically a 4-quadrant >>>>>>>>>>diode thing or a Gilbert cell type circuit. Or a 2-quadrant >>>>>>>>>>thing like a pentode. Or even a single diode. All do some flavor >>>>>>>>>>of multiplying.

    Some mixers inherently multiply a signal by a square wave, which >>>>>>>>>>resembles other multiplier-type things once you lowpass filter >>>>>>>>>>the output. That's a "synchronous detector", which we usually do >>>>>>>>>>in an FPGA.

    A sampler is a signal multiplier too.

    These are all variations on the basic idea of multiplying two >>>>>>>>>>signals.

    A the word 'mixer' in RF is not the same as a multiplier,,
    Multipliers are like harmonic generating stages say you have a 1 >>>>>>>>> MHz distorted sine wave and then a second stage tuned at 3
    MHz,..
    turned to third harmonic.

    mamamatical speaking RF mixing is indeed multiplication.

    Like Shakepierce once said:
    "What's in a name..." CocaCola wihout coke

    I think in this context, HP is using the term "sampler" to mean >>>>>>>>something which 'sniffs' a small amount of a signal for testing >>>>>>>>purposes. Like a few turns of wire around a transmission line will >>>>>>>>'sniff' a small sample of what's going on in the line.
    Where I went wrong was rigidly thinking HP meant 'sampling' in the >>>>>>>>manner a sampling oscilloscope works. That's what threw me. I tend >>>>>>>>to interpret things very literally. :(

    Would be nice to see a real circuit diagram of that thing.
    What is the model / type number?
    I am curious.
    So far I have been able to find circuits for most stuff I came
    across with google.

    It's the HP8566B - a very well known lab-grade analyser of the day >>>>>>which many RF designers still use. There is a *ton* of service info >>>>>>on this model online. However, I have not been able to see a >>>>>>*proper* schematic for the "sampler" in the A11A5 board which is >>>>>>where the issue is.

    OK, thank you, I will google a bit..
    I got the user manual now:
    https://elektrotanya.com/ >>>>hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- >>>>programming_1984_sm.pdf/download.html#dl
    Then trouble shooting manual part 1
    https://xdevs.com/doc/HP_Agilent_Keysight/ >>>>HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf
    Seems to have at least some circuits (just a quick look)
    and part 2
    https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, >>>>%208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf
    also has some circuits I will have a look at the hundreds of pages,
    will take some time.
    I presume you have these?
    Took 10 seconds to find with google

    Yes, I have all of those and more. I think altogether there are 7 very >>>>large manuals for this analyser. However, I've not been able to find a >>>>single actual schematic which gives component level detail of what
    they call the "sampler" - and that's unusual, as they've given a great >>>>deal of attention to providing very full service details in all other >>>>respects.

    Will read some of it and let you know what I come up with ..

    OK have flipped through all circuit diagrams in the thing.

    It looks to me like a heterodyne down converter followed by a narrow
    filter IF stage tuned over the whole frequency range.
    No sampling on the input signal at all.
    Just a RF mixer.
    PLLs in the tuned oscillator that are used to scan the band.

    Like an old AM shortwave radio where you turn the big tuning knob
    really fast mechanically to see the amplitude of each station on the
    cats eye as you tune over the whole receive spectrum.
    spectrum width set by the 450 kHz or so IF filter stages in those
    radio days....
    To get the IF narrow enough I did notice some crystal filter?, multi
    stage RC filters?
    Scanning the band takes time that way... horizontal deflection scope,
    amplitude on vertical deflection scope..
    Does it have a long persistence screen?
    That way you can point at any small section of the input like long
    wave / medium wave / shortwave in the old radios.
    Also because I do not see any Fourier transform / computah /
    computation..

    That thing is from 1987? enough computah power back then for Fourier
    transform?

    I could be wrong though, more than a 1000 pages read in... lemme
    see... an hour.
    Need to sleep on it and look again.
    Rest is just scope trace drive and power supplies..
    Its all so easy:
    https://panteltje.nl/panteltje/scope_tv/index.html
    HP should have added a teefee mode, but alas, analog teefee is dead in
    most of the world these days.

    This is more fun:
    OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so,
    https://www.ebay.com/p/22032165355?iid=335019807057

    Use a Raspberry Pi or a PC ..

    I remember when I build a frequency counter with nixy tubes and TTL
    and 100 kHz crystal took it to work (tube days) it blew the guys
    away.. Then demoed it at the local ham group connected to the local
    oscillator of a shortwave receiver Explained 'subtract the IF
    frequency from the indicated frequency to get the real frequency'
    Most radios have that now with nice LCD screens and PLL local
    oscillators.... Or now even direct sampling like that SDR_RTL stuff.


    I personally would dump the HP thing.. or maybe donate it to some
    museum..

    Haha! No, neither of those things are going to happen, Jan. I'm still >>suffering from PTSD at having to toss a Tek 555 into a dumpster 20 years >>ago.
    Plus...... I've ordered *another* HP boat anchor to assist me to fix
    this one! You can never have too many boat anchors (although of course,
    I have). :)

    Yes, the Tek 555
    https://w140.com/tekwiki/wiki/555
    I likely used that one in those early sixties :-)
    Keep it, good analog scopes are rare...
    I still use my Trio-CS1562 analog scope:
    https://panteltje.nl/pub/
    APC_UPS_ES700_waveform_25W_edison_bulb_load_IMG_0270.JPG
    it has thousands of hours, was on all day in my TV repair shop..

    But space is always a problem, I have located many times, other
    countries, donated everything, start new.
    Same for old cars I have driven..
    Citroen 2CV, Peugeot 404 station, Ford Mustang V8, some memories...
    Why did you dump the Tek?
    Those are easy to repair.

    I moved overseas and couldn't hold on to everything, sadly. Didn't have
    time to find a museum either.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to Doom on Fri Aug 2 05:11:43 2024
    On a sunny day (Thu, 1 Aug 2024 08:27:16 -0000 (UTC)) it happened Cursitor
    Doom <cd999666@notformail.com> wrote in <v8fgt4$231a4$1@dont-email.me>:

    ...
    I moved overseas and couldn't hold on to everything, sadly. Didn't have
    time to find a museum either.


    As to repair / fault finding of that thing we were talking about,
    I dunno what the symptoms are?
    But after letting the 100 pages or so sink in in my brain:
    Like somebody mentioned, check power supply (caps) for ripple with a scope, supply voltages.

    Likely source of damage is the input stage (may have been overloaded, manual shows strict limits)

    So, put some 100 MHz or so signal on the input, check with a scope if it reaches the first mixer stage
    check if something comes out of that mixer stage.
    If not check if the local oscillator signal is present at the mixer stage
    if all OK go for the next mixer,
    If all OK check if the sweep generator works so the local oscillator is actually sweeped,
    check if any signal in the (20 MHz or so?) first IF stages,
    basically follow the signal path.
    With all the boat anchors you have 'floating??' about those measurements should be easy.
    All OK so far and display scope working at least you should see a trace with something on it

    Need more info on what the problem is, should not take more than a hour that way.
    If something with the other electronics.. have not looked at it much.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Jan Panteltje on Fri Aug 2 10:09:24 2024
    On Fri, 02 Aug 2024 05:11:43 GMT, Jan Panteltje wrote:

    On a sunny day (Thu, 1 Aug 2024 08:27:16 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in <v8fgt4$231a4$1@dont-email.me>:

    ...
    I moved overseas and couldn't hold on to everything, sadly. Didn't have >>time to find a museum either.


    As to repair / fault finding of that thing we were talking about,
    I dunno what the symptoms are?
    But after letting the 100 pages or so sink in in my brain:
    Like somebody mentioned, check power supply (caps) for ripple with a
    scope,
    supply voltages.

    Yes, first thing I did. And replaced any suspect caps.

    Likely source of damage is the input stage (may have been overloaded,
    manual shows strict limits)

    No, the input stage is fine. I can see all the local FM stations at their expected strength levels - but they appear to be about 20Mhz lower than
    they are!

    So, put some 100 MHz or so signal on the input, check with a scope if it reaches the first mixer stage check if something comes out of that mixer stage.
    If not check if the local oscillator signal is present at the mixer
    stage if all OK go for the next mixer,
    If all OK check if the sweep generator works so the local oscillator is actually sweeped,
    check if any signal in the (20 MHz or so?) first IF stages,
    basically follow the signal path.
    With all the boat anchors you have 'floating??' about those measurements should be easy.
    All OK so far and display scope working at least you should see a trace
    with something on it

    Need more info on what the problem is, should not take more than a hour
    that way.
    If something with the other electronics.. have not looked at it much.

    Self-diagnostics have localised the fault to within the YTO loop and my subsequent investigations have narrowed down this issue with the 'greater "sampler" stage' putting out garbage. As I said further up the thread,
    either there's an issue with the 'sampler' itself or it's just doing its
    best with faulty input signals: garbage in/garbage out.
    There are 3 inputs to the section: fM/N, f20/30 and fYTO. All those
    signals are present and their power levels are fine. But I need to ensure
    their frequencies correspond to the charts provided in the manual and the relevant derivation formulas. If not, the loop has no chance to lock.
    My biggest problem is finding the time to fit it in!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to Doom on Fri Aug 2 12:02:43 2024
    On a sunny day (Fri, 2 Aug 2024 10:09:24 -0000 (UTC)) it happened Cursitor
    Doom <cd999666@notformail.com> wrote in <v8ib8k$2p2d8$1@dont-email.me>:

    On Fri, 02 Aug 2024 05:11:43 GMT, Jan Panteltje wrote:

    On a sunny day (Thu, 1 Aug 2024 08:27:16 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8fgt4$231a4$1@dont-email.me>:

    ...
    I moved overseas and couldn't hold on to everything, sadly. Didn't have >>>time to find a museum either.


    As to repair / fault finding of that thing we were talking about,
    I dunno what the symptoms are?
    But after letting the 100 pages or so sink in in my brain:
    Like somebody mentioned, check power supply (caps) for ripple with a
    scope,
    supply voltages.

    Yes, first thing I did. And replaced any suspect caps.

    Likely source of damage is the input stage (may have been overloaded,
    manual shows strict limits)

    No, the input stage is fine. I can see all the local FM stations at their >expected strength levels - but they appear to be about 20Mhz lower than
    they are!

    The 'about' 20 MHz is susicous, as the IF is 21.4 MHz.
    Looks almost like a problem with the calibration
    On page 12 of the manual I see an internal reference output,
    is that 10 MHz correct?
    What happens when yu feed in 10 MHz from an other source?
    quote from that page:
    To lock the spectrum analyzer to an external frequency reference, set the FREQ REFERENCE
    Analyzer performance will be degraded unless frequency reference phase noise and spurious sign
    dBc single sideband (1 Hz) referred to 10 MHz at a 100 Hz to 10 kHz offset. To lock another spect
    the spectrum analyzer internal frequency reference, set the FREQ REFERENCE switch to INT



    So, put some 100 MHz or so signal on the input, check with a scope if it
    reaches the first mixer stage check if something comes out of that mixer
    stage.
    If not check if the local oscillator signal is present at the mixer
    stage if all OK go for the next mixer,
    If all OK check if the sweep generator works so the local oscillator is
    actually sweeped,
    check if any signal in the (20 MHz or so?) first IF stages,
    basically follow the signal path.
    With all the boat anchors you have 'floating??' about those measurements
    should be easy.
    All OK so far and display scope working at least you should see a trace
    with something on it

    Need more info on what the problem is, should not take more than a hour
    that way.
    If something with the other electronics.. have not looked at it much.

    Self-diagnostics have localised the fault to within the YTO loop and my >subsequent investigations have narrowed down this issue with the 'greater >"sampler" stage' putting out garbage. As I said further up the thread,
    either there's an issue with the 'sampler' itself or it's just doing its
    best with faulty input signals: garbage in/garbage out.
    There are 3 inputs to the section: fM/N, f20/30 and fYTO. All those
    signals are present and their power levels are fine. But I need to ensure >their frequencies correspond to the charts provided in the manual and the >relevant derivation formulas. If not, the loop has no chance to lock.
    My biggest problem is finding the time to fit it in!

    OK, we will wait and see.
    If all else fails, this was fun to create:
    https://panteltje.nl/panteltje/pic/scope_pic/
    https://panteltje.nl/panteltje/pic/scope_pic/screen_dump2.txt

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Jan Panteltje on Fri Aug 2 15:59:32 2024
    On Fri, 02 Aug 2024 12:02:43 GMT, Jan Panteltje wrote:

    On a sunny day (Fri, 2 Aug 2024 10:09:24 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in <v8ib8k$2p2d8$1@dont-email.me>:

    On Fri, 02 Aug 2024 05:11:43 GMT, Jan Panteltje wrote:

    On a sunny day (Thu, 1 Aug 2024 08:27:16 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8fgt4$231a4$1@dont-email.me>:

    ...
    I moved overseas and couldn't hold on to everything, sadly. Didn't
    have time to find a museum either.


    As to repair / fault finding of that thing we were talking about,
    I dunno what the symptoms are?
    But after letting the 100 pages or so sink in in my brain:
    Like somebody mentioned, check power supply (caps) for ripple with a
    scope,
    supply voltages.

    Yes, first thing I did. And replaced any suspect caps.

    Likely source of damage is the input stage (may have been overloaded,
    manual shows strict limits)

    No, the input stage is fine. I can see all the local FM stations at
    their expected strength levels - but they appear to be about 20Mhz lower >>than they are!

    The 'about' 20 MHz is susicous, as the IF is 21.4 MHz.
    Looks almost like a problem with the calibration On page 12 of the
    manual I see an internal reference output,
    is that 10 MHz correct?
    What happens when yu feed in 10 MHz from an other source?
    quote from that page:
    To lock the spectrum analyzer to an external frequency reference, set
    the FREQ REFERENCE Analyzer performance will be degraded unless
    frequency reference phase noise and spurious sign dBc single sideband
    (1 Hz) referred to 10 MHz at a 100 Hz to 10 kHz offset. To lock
    another spect the spectrum analyzer internal frequency reference, set
    the FREQ REFERENCE switch to INT



    So, put some 100 MHz or so signal on the input, check with a scope if
    it reaches the first mixer stage check if something comes out of that
    mixer stage.
    If not check if the local oscillator signal is present at the mixer
    stage if all OK go for the next mixer,
    If all OK check if the sweep generator works so the local oscillator
    is actually sweeped,
    check if any signal in the (20 MHz or so?) first IF stages,
    basically follow the signal path.
    With all the boat anchors you have 'floating??' about those
    measurements should be easy.
    All OK so far and display scope working at least you should see a
    trace with something on it

    Need more info on what the problem is, should not take more than a
    hour that way.
    If something with the other electronics.. have not looked at it much.

    Self-diagnostics have localised the fault to within the YTO loop and my >>subsequent investigations have narrowed down this issue with the
    'greater "sampler" stage' putting out garbage. As I said further up the >>thread, either there's an issue with the 'sampler' itself or it's just >>doing its best with faulty input signals: garbage in/garbage out.
    There are 3 inputs to the section: fM/N, f20/30 and fYTO. All those
    signals are present and their power levels are fine. But I need to
    ensure their frequencies correspond to the charts provided in the manual >>and the relevant derivation formulas. If not, the loop has no chance to >>lock.
    My biggest problem is finding the time to fit it in!

    OK, we will wait and see.
    If all else fails, this was fun to create:
    https://panteltje.nl/panteltje/pic/scope_pic/
    https://panteltje.nl/panteltje/pic/scope_pic/screen_dump2.txt

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Jan Panteltje on Fri Aug 2 16:08:38 2024
    On Fri, 02 Aug 2024 12:02:43 GMT, Jan Panteltje wrote:

    On a sunny day (Fri, 2 Aug 2024 10:09:24 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in <v8ib8k$2p2d8$1@dont-email.me>:

    On Fri, 02 Aug 2024 05:11:43 GMT, Jan Panteltje wrote:

    On a sunny day (Thu, 1 Aug 2024 08:27:16 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8fgt4$231a4$1@dont-email.me>:

    ...
    I moved overseas and couldn't hold on to everything, sadly. Didn't
    have time to find a museum either.


    As to repair / fault finding of that thing we were talking about,
    I dunno what the symptoms are?
    But after letting the 100 pages or so sink in in my brain:
    Like somebody mentioned, check power supply (caps) for ripple with a
    scope,
    supply voltages.

    Yes, first thing I did. And replaced any suspect caps.

    Likely source of damage is the input stage (may have been overloaded,
    manual shows strict limits)

    No, the input stage is fine. I can see all the local FM stations at
    their expected strength levels - but they appear to be about 20Mhz lower >>than they are!

    The 'about' 20 MHz is susicous, as the IF is 21.4 MHz.

    There are several IFs, none of which none are 21.4Mhz according to the
    notes in the text. They state the IF changes according to band, so it's 3621.4Mhz for band 0, -321.4Mhz for band 1 and +321.4Mhz for bands 2, 3
    and 4.

    Looks almost like a problem with the calibration On page 12 of the
    manual I see an internal reference output,
    is that 10 MHz correct?

    Yes.

    What happens when yu feed in 10 MHz from an other source?

    What's your thinking in that suggestion? What difference could it make?

    quote from that page:
    To lock the spectrum analyzer to an external frequency reference, set
    the FREQ REFERENCE Analyzer performance will be degraded unless
    frequency reference phase noise and spurious sign dBc single sideband
    (1 Hz) referred to 10 MHz at a 100 Hz to 10 kHz offset. To lock
    another spect the spectrum analyzer internal frequency reference, set
    the FREQ REFERENCE switch to INT

    Well, I've just wasted several more futile hours trying to make sense of
    the figures given in the manuals. This thing is a *bitch* it is *so* complicated. I've never had to deal with something of this nature before
    in all my decades in the hobby. Much of the problem is having to rely on
    PDF manuals and HP having spread the relevant information over several different manuals covering thousands of pages. Nice work, HP!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to Doom on Sat Aug 3 05:52:22 2024
    On a sunny day (Fri, 2 Aug 2024 16:08:38 -0000 (UTC)) it happened Cursitor
    Doom <cd999666@notformail.com> wrote in <v8j0a6$2t2o7$2@dont-email.me>:

    On Fri, 02 Aug 2024 12:02:43 GMT, Jan Panteltje wrote:

    On a sunny day (Fri, 2 Aug 2024 10:09:24 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8ib8k$2p2d8$1@dont-email.me>:

    On Fri, 02 Aug 2024 05:11:43 GMT, Jan Panteltje wrote:

    On a sunny day (Thu, 1 Aug 2024 08:27:16 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8fgt4$231a4$1@dont-email.me>:

    ...
    I moved overseas and couldn't hold on to everything, sadly. Didn't >>>>>have time to find a museum either.


    As to repair / fault finding of that thing we were talking about,
    I dunno what the symptoms are?
    But after letting the 100 pages or so sink in in my brain:
    Like somebody mentioned, check power supply (caps) for ripple with a
    scope,
    supply voltages.

    Yes, first thing I did. And replaced any suspect caps.

    Likely source of damage is the input stage (may have been overloaded,
    manual shows strict limits)

    No, the input stage is fine. I can see all the local FM stations at
    their expected strength levels - but they appear to be about 20Mhz lower >>>than they are!

    The 'about' 20 MHz is susicous, as the IF is 21.4 MHz.

    There are several IFs, none of which none are 21.4Mhz according to the
    notes in the text. They state the IF changes according to band, so it's >3621.4Mhz for band 0, -321.4Mhz for band 1 and +321.4Mhz for bands 2, 3
    and 4.

    Page 10 of the manual, quote:
    rear panel IF outputs
    21.4 MHz IF Output




    Looks almost like a problem with the calibration On page 12 of the
    manual I see an internal reference output,
    is that 10 MHz correct?

    Yes.

    What happens when yu feed in 10 MHz from an other source?

    What's your thinking in that suggestion? What difference could it make?

    quote from that page:
    To lock the spectrum analyzer to an external frequency reference, set
    the FREQ REFERENCE Analyzer performance will be degraded unless
    frequency reference phase noise and spurious sign dBc single sideband
    (1 Hz) referred to 10 MHz at a 100 Hz to 10 kHz offset. To lock
    another spect the spectrum analyzer internal frequency reference, set
    the FREQ REFERENCE switch to INT

    Well, I've just wasted several more futile hours trying to make sense of
    the figures given in the manuals. This thing is a *bitch* it is *so* >complicated. I've never had to deal with something of this nature before
    in all my decades in the hobby. Much of the problem is having to rely on
    PDF manuals and HP having spread the relevant information over several >different manuals covering thousands of pages. Nice work, HP!

    I agree, in broadcasting we demanded full circuit diagrams and support from any manufacturer that
    we had equipment from.
    And spare parts too..
    Else no buy
    I remember going to an Ampex training for 3 weeks in Germany for their latest video tape recorders
    coming back with several kg of schematics and papers.
    That HP documentation is crap, the drawings suck, looks to me they are very hard trying to hide how it really works,
    or the one who 'painted' it had no clue, or both.
    It would never have been accepted by us.
    But that HP stuff is simple compared to what was around in a studio.

    A simple block diagram would be a good idea.
    But they do not even know how to draw a signal path, using arrows for connectors, crap.

    Anyways, just use you shortwave radio, or soundcard, or better even a rtl_sdr stick.
    Using the SSB mode in shortwave with a decent modern radio, like my Tecsun portable
    allows you to tune to a few Hz (zero carrier beep).

    Do you have a boat? Anchors are useful.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Jan Panteltje on Sat Aug 3 11:27:15 2024
    On Sat, 03 Aug 2024 05:52:22 GMT, Jan Panteltje wrote:

    On a sunny day (Fri, 2 Aug 2024 16:08:38 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in <v8j0a6$2t2o7$2@dont-email.me>:

    On Fri, 02 Aug 2024 12:02:43 GMT, Jan Panteltje wrote:

    On a sunny day (Fri, 2 Aug 2024 10:09:24 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8ib8k$2p2d8$1@dont-email.me>:

    On Fri, 02 Aug 2024 05:11:43 GMT, Jan Panteltje wrote:

    On a sunny day (Thu, 1 Aug 2024 08:27:16 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in
    <v8fgt4$231a4$1@dont-email.me>:

    ...
    I moved overseas and couldn't hold on to everything, sadly. Didn't >>>>>>have time to find a museum either.


    As to repair / fault finding of that thing we were talking about,
    I dunno what the symptoms are?
    But after letting the 100 pages or so sink in in my brain:
    Like somebody mentioned, check power supply (caps) for ripple with a >>>>> scope,
    supply voltages.

    Yes, first thing I did. And replaced any suspect caps.

    Likely source of damage is the input stage (may have been
    overloaded,
    manual shows strict limits)

    No, the input stage is fine. I can see all the local FM stations at >>>>their expected strength levels - but they appear to be about 20Mhz >>>>lower than they are!

    The 'about' 20 MHz is susicous, as the IF is 21.4 MHz.

    There are several IFs, none of which none are 21.4Mhz according to the >>notes in the text. They state the IF changes according to band, so it's >>3621.4Mhz for band 0, -321.4Mhz for band 1 and +321.4Mhz for bands 2, 3
    and 4.

    Page 10 of the manual, quote:
    rear panel IF outputs
    21.4 MHz IF Output

    Wow! What a lot of IFs!





    Looks almost like a problem with the calibration On page 12 of the
    manual I see an internal reference output,
    is that 10 MHz correct?

    Yes.

    What happens when yu feed in 10 MHz from an other source?

    What's your thinking in that suggestion? What difference could it make?

    quote from that page:
    To lock the spectrum analyzer to an external frequency reference,
    set the FREQ REFERENCE Analyzer performance will be degraded unless
    frequency reference phase noise and spurious sign dBc single
    sideband (1 Hz) referred to 10 MHz at a 100 Hz to 10 kHz offset. To
    lock another spect the spectrum analyzer internal frequency
    reference, set the FREQ REFERENCE switch to INT

    Well, I've just wasted several more futile hours trying to make sense of >>the figures given in the manuals. This thing is a *bitch* it is *so* >>complicated. I've never had to deal with something of this nature before
    in all my decades in the hobby. Much of the problem is having to rely on >>PDF manuals and HP having spread the relevant information over several >>different manuals covering thousands of pages. Nice work, HP!

    I agree, in broadcasting we demanded full circuit diagrams and support
    from any manufacturer that we had equipment from.
    And spare parts too..
    Else no buy I remember going to an Ampex training for 3 weeks in Germany
    for their latest video tape recorders coming back with several kg of schematics and papers.
    That HP documentation is crap, the drawings suck, looks to me they are
    very hard trying to hide how it really works,
    or the one who 'painted' it had no clue, or both.
    It would never have been accepted by us.
    But that HP stuff is simple compared to what was around in a studio.

    A simple block diagram would be a good idea.
    But they do not even know how to draw a signal path, using arrows
    for connectors, crap.

    Anyways, just use you shortwave radio, or soundcard, or better even a
    rtl_sdr stick.
    Using the SSB mode in shortwave with a decent modern radio, like my
    Tecsun portable allows you to tune to a few Hz (zero carrier beep).

    Do you have a boat? Anchors are useful.

    They are indeed. And perhaps that's the best use for all these many and
    various HP manuals! :-D

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to Doom on Sat Aug 3 12:34:44 2024
    On a sunny day (Sat, 3 Aug 2024 11:27:15 -0000 (UTC)) it happened Cursitor
    Doom <cd999666@notformail.com> wrote in <v8l46j$3e34d$1@dont-email.me>:

    There are several IFs, none of which none are 21.4Mhz according to the >>>notes in the text. They state the IF changes according to band, so it's >>>3621.4Mhz for band 0, -321.4Mhz for band 1 and +321.4Mhz for bands 2, 3 >>>and 4.

    Page 10 of the manual, quote:
    rear panel IF outputs
    21.4 MHz IF Output

    Wow! What a lot of IFs!

    In
    HP_8566B_troubleshooting_and_repair_1.pdf
    On page 55 see the 24.1 MHz originating from block A4A8A1
    then pasing through a gain control block A4A5,

    On page 57 you see it being processed
    selectable bandwidth control A4A4
    log amplifer with filters A4A3
    log detector A2A2
    and then to the recorder outputs (top left page 55)

    The control part 'A4A9 IF control'
    selects what you want to see.

    So it seems to me the 24.1 MHz is the final filter?

    It _is_ possible the graticule display is wrong not the display it self...
    wild guess though, would need to measure some stuff.
    Or maybe one of the PLL loops is locked at the wrong frequency.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Jan Panteltje on Sat Aug 3 20:43:12 2024
    On Sat, 03 Aug 2024 12:34:44 GMT, Jan Panteltje wrote:

    On a sunny day (Sat, 3 Aug 2024 11:27:15 -0000 (UTC)) it happened
    Cursitor Doom <cd999666@notformail.com> wrote in <v8l46j$3e34d$1@dont-email.me>:

    There are several IFs, none of which none are 21.4Mhz according to the >>>>notes in the text. They state the IF changes according to band, so
    it's 3621.4Mhz for band 0, -321.4Mhz for band 1 and +321.4Mhz for
    bands 2, 3 and 4.

    Page 10 of the manual, quote:
    rear panel IF outputs
    21.4 MHz IF Output

    Wow! What a lot of IFs!

    In
    HP_8566B_troubleshooting_and_repair_1.pdf
    On page 55 see the 24.1 MHz originating from block A4A8A1
    then pasing through a gain control block A4A5,

    On page 57 you see it being processed
    selectable bandwidth control A4A4 log amplifer with filters A4A3 log
    detector A2A2
    and then to the recorder outputs (top left page 55)

    The control part 'A4A9 IF control'
    selects what you want to see.

    So it seems to me the 24.1 MHz is the final filter?

    It _is_ possible the graticule display is wrong not the display it
    self...
    wild guess though, would need to measure some stuff.
    Or maybe one of the PLL loops is locked at the wrong frequency.

    I've got several hours tomorrow to look further into this, Jan. I have
    some useful info to apply to the problem........

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)