• OT: sound speed depends on frequency on mars

    From Jan Panteltje@21:1/5 to All on Fri Aug 30 11:13:05 2024
    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main
    At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Fri Aug 30 07:34:05 2024
    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main
    At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...




    Funny, I just delivered a lecture on transmission lines and noted that microstrips have dispersion from the unbalanced dielectric constants
    and skin effect. Rising edges get sloppy at the and of a long trace.

    I wonder if anyone has added surface-mount Heaviside loading coils to
    a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    There used to be millions of 88 mH toroids on the surplus market,
    telephone loading coils.

    The Mars thing is no big deal. You'd be dead too soon to worry about
    acoustics. Imagine Burning Man (literally!) on Mars.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Sat Aug 31 01:23:19 2024
    On 31/08/2024 12:34 am, john larkin wrote:
    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main
    At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...

    Funny, I just delivered a lecture on transmission lines and noted that microstrips have dispersion from the unbalanced dielectric constants
    and skin effect. Rising edges get sloppy at the and of a long trace.

    I hope you pointed out that buried strip-line isn't dispersive. I have
    pointed this out here from time to time.

    https://www.wevolver.com/article/stripline-vs-microstrip
    I wonder if anyone has added surface-mount Heaviside loading coils to
    a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    It would be a bit silly. You can make lumped constant transmission lines
    by linking a series of capacitors with discrete inductors, if you want a
    high impedance transmission line - people sold them thick film hybrid assemblies, and I even used a few, a very long time ago.

    There used to be millions of 88 mH toroids on the surplus market,
    telephone loading coils.

    The Mars thing is no big deal. You'd be dead too soon to worry about acoustics. Imagine Burning Man (literally!) on Mars.

    Unless you wore a pressure suit. Not exactly the usual music festival
    costume, but you'd need to wear one to survive an outdoor concert on Mars.

    --
    Bill Sloman,

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to All on Fri Aug 30 10:10:47 2024
    On Sat, 31 Aug 2024 01:23:19 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 31/08/2024 12:34 am, john larkin wrote:
    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main
    At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...

    Funny, I just delivered a lecture on transmission lines and noted that
    microstrips have dispersion from the unbalanced dielectric constants
    and skin effect. Rising edges get sloppy at the and of a long trace.

    I hope you pointed out that buried strip-line isn't dispersive. I have >pointed this out here from time to time.

    Of course it's dispersive, maybe a bit less than microstrip.

    It's hard to keep up decent impedances on stripline in a multilayer
    board, especially 8 or 10 layers.


    https://www.wevolver.com/article/stripline-vs-microstrip
    I wonder if anyone has added surface-mount Heaviside loading coils to
    a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    It would be a bit silly.

    Most ideas seem silly to people who are by nature hostile to ideas.

    Dismissing is easier than thinking.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Sat Aug 31 16:17:39 2024
    On 31/08/2024 3:10 am, john larkin wrote:
    On Sat, 31 Aug 2024 01:23:19 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 31/08/2024 12:34 am, john larkin wrote:
    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main >>>> At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...

    Funny, I just delivered a lecture on transmission lines and noted that
    microstrips have dispersion from the unbalanced dielectric constants
    and skin effect. Rising edges get sloppy at the and of a long trace.

    I hope you pointed out that buried strip-line isn't dispersive. I have
    pointed this out here from time to time.

    Of course it's dispersive, maybe a bit less than microstrip.

    Why do you think that?

    It's hard to keep up decent impedances on stripline in a multilayer
    board, especially 8 or 10 layers.

    Stripline is buried between two ground planes. The only tricky part of impedance control is the thickness of the dielectric in the two layers
    above and below the strip-line. In a ten layer board this is thinner
    than it would be in a board with fewer layers.

    Pay enough for close-tolerance substrates in the two relevant layers and
    you should be okay.

    https://www.wevolver.com/article/stripline-vs-microstrip

    I wonder if anyone has added surface-mount Heaviside loading coils to
    a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    It would be a bit silly.

    Most ideas seem silly to people who are by nature hostile to ideas.

    Not a problem I've got.

    Dismissing is easier than thinking.

    Thinking about what a loading coil might be doing to the impedance of a
    PCB trace isn't something that you seem to have managed to do.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to All on Sat Aug 31 07:31:52 2024
    On a sunny day (Fri, 30 Aug 2024 07:34:05 -0700) it happened john larkin <jlarkin_highland_tech> wrote in <vgl3dj9uq2t9bmo6miqr8faaiuoi1d24c2@4ax.com>:

    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main
    At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough
    time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s)
    faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you
    would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...




    Funny, I just delivered a lecture on transmission lines and noted that >microstrips have dispersion from the unbalanced dielectric constants
    and skin effect. Rising edges get sloppy at the and of a long trace.

    I wonder if anyone has added surface-mount Heaviside loading coils to
    a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    There used to be millions of 88 mH toroids on the surplus market,
    telephone loading coils.

    The Mars thing is no big deal. You'd be dead too soon to worry about >acoustics. Imagine Burning Man (literally!) on Mars.

    It may matter for sonar based systems, distance measurements etc..
    I have some small sonar based modules in use from ebay, something like these:
    https://www.ebay.nl/itm/185960647108

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Sat Aug 31 07:18:58 2024
    On Sat, 31 Aug 2024 16:17:39 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 31/08/2024 3:10 am, john larkin wrote:
    On Sat, 31 Aug 2024 01:23:19 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 31/08/2024 12:34 am, john larkin wrote:
    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main >>>>> At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...

    Funny, I just delivered a lecture on transmission lines and noted that >>>> microstrips have dispersion from the unbalanced dielectric constants
    and skin effect. Rising edges get sloppy at the and of a long trace.

    I hope you pointed out that buried strip-line isn't dispersive. I have
    pointed this out here from time to time.

    Of course it's dispersive, maybe a bit less than microstrip.

    Why do you think that?

    Because dielectrics are imperfect, especially FR4, and because there
    are lots of papers online that analyze dispersion in stripline.


    It's hard to keep up decent impedances on stripline in a multilayer
    board, especially 8 or 10 layers.

    Stripline is buried between two ground planes. The only tricky part of >impedance control is the thickness of the dielectric in the two layers
    above and below the strip-line. In a ten layer board this is thinner
    than it would be in a board with fewer layers.

    And eventually the trace has to be skinnier than PCB houses are
    willing to etch. Standard pricing seems to be around 5 or maybe 4 mils
    width these days. We do a lot of 5, to sneak between BGA balls, but
    sometimes even 5 is too big.

    Thin dielectrics have tolerance issues too. I'm talking about real
    PCBs here, not ideal theoretical stuff.


    Pay enough for close-tolerance substrates in the two relevant layers and
    you should be okay.

    "Pay enough" can get crazy fast. I don't want to pay hundreds of
    dollars for a smallish PCB.


    https://www.wevolver.com/article/stripline-vs-microstrip

    I wonder if anyone has added surface-mount Heaviside loading coils to
    a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    It would be a bit silly.

    Most ideas seem silly to people who are by nature hostile to ideas.

    Not a problem I've got.

    Dismissing is easier than thinking.

    Thinking about what a loading coil might be doing to the impedance of a
    PCB trace isn't something that you seem to have managed to do.

    I certainly had the idea. I might Spice a bunch of ltlines with
    inductors between, just for fun. It's unlikely that I'd use such an
    arrangement in real life, but it's just possible, especially if analog
    quality of a fast edge matters, like in a laser modulator maybe. It's preferable to just keep all the traces very short, but that's not
    always possible.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Sun Sep 1 02:37:22 2024
    On 1/09/2024 12:18 am, john larkin wrote:
    On Sat, 31 Aug 2024 16:17:39 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 31/08/2024 3:10 am, john larkin wrote:
    On Sat, 31 Aug 2024 01:23:19 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 31/08/2024 12:34 am, john larkin wrote:
    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid> >>>>> wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main >>>>>> At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...

    Funny, I just delivered a lecture on transmission lines and noted that >>>>> microstrips have dispersion from the unbalanced dielectric constants >>>>> and skin effect. Rising edges get sloppy at the and of a long trace.

    I hope you pointed out that buried strip-line isn't dispersive. I have >>>> pointed this out here from time to time.

    Of course it's dispersive, maybe a bit less than microstrip.

    Why do you think that?

    Because dielectrics are imperfect, especially FR4, and because there
    are lots of papers online that analyze dispersion in stripline.

    But you can't cite any of them. You wouldn't use FR4 around a stripline
    if you wanted a low-dispersion transmission line. There are better
    substrates his frequency work.

    It's hard to keep up decent impedances on stripline in a multilayer
    board, especially 8 or 10 layers.

    Stripline is buried between two ground planes. The only tricky part of
    impedance control is the thickness of the dielectric in the two layers
    above and below the strip-line. In a ten layer board this is thinner
    than it would be in a board with fewer layers.

    And eventually the trace has to be skinnier than PCB houses are
    willing to etch.

    Why?

    Standard pricing seems to be around 5 or maybe 4 mils
    width these days. We do a lot of 5, to sneak between BGA balls, but
    sometimes even 5 is too big.

    Thin dielectrics have tolerance issues too. I'm talking about real
    PCBs here, not ideal theoretical stuff.

    Printed circuit board are always real.

    Pay enough for close-tolerance substrates in the two relevant layers and
    you should be okay.

    "Pay enough" can get crazy fast. I don't want to pay hundreds of
    dollars for a smallish PCB.

    An eight or ten layer PCB isn't going to be small. You only need lots of
    layers when you have to connect lots of stuff.
    https://www.wevolver.com/article/stripline-vs-microstrip

    I wonder if anyone has added surface-mount Heaviside loading coils to >>>>> a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    It would be a bit silly.

    John snipped the rest of that senstence, without marking the snip.

    You can make lumped constant transmission lines by linking a
    series >>>> of capacitors with discrete inductors, if you want a high
    impedance >>>> transmission line - people sold them as thick film hybrid
    assemblies, and I even used a few, a very long time ago.

    Most ideas seem silly to people who are by nature hostile to ideas.

    Not a problem I've got.

    Dismissing is easier than thinking.

    Thinking about what a loading coil might be doing to the impedance of a
    PCB trace isn't something that you seem to have managed to do.

    I certainly had the idea.

    In a remarkably half-baked way.

    I might Spice a bunch of ltlines with
    inductors between, just for fun. It's unlikely that I'd use such an arrangement in real life, but it's just possible, especially if analog quality of a fast edge matters, like in a laser modulator maybe. It's preferable to just keep all the traces very short, but that's not
    always possible.

    You seem to be intent on re-inventing the lumped constant delay line,
    without being aware that they were commercially available some thirty
    years ago, back when I used them. They may still be available.

    Back around 1985 we planned on making one of our own when we wanted a microsecond or so of pure delay on the main signal to synchronise it
    with the small second order corrections we were adding in from a couple
    of analog multipliers (which had their own propagation delay).

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Sat Aug 31 12:31:36 2024
    On Sun, 1 Sep 2024 02:37:22 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 1/09/2024 12:18 am, john larkin wrote:
    On Sat, 31 Aug 2024 16:17:39 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 31/08/2024 3:10 am, john larkin wrote:
    On Sat, 31 Aug 2024 01:23:19 +1000, Bill Sloman <bill.sloman@ieee.org> >>>> wrote:

    On 31/08/2024 12:34 am, john larkin wrote:
    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid> >>>>>> wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main >>>>>>> At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...

    Funny, I just delivered a lecture on transmission lines and noted that >>>>>> microstrips have dispersion from the unbalanced dielectric constants >>>>>> and skin effect. Rising edges get sloppy at the and of a long trace. >>>>>
    I hope you pointed out that buried strip-line isn't dispersive. I have >>>>> pointed this out here from time to time.

    Of course it's dispersive, maybe a bit less than microstrip.

    Why do you think that?

    Because dielectrics are imperfect, especially FR4, and because there
    are lots of papers online that analyze dispersion in stripline.

    But you can't cite any of them.

    Can't you google?


    You wouldn't use FR4 around a stripline
    if you wanted a low-dispersion transmission line. There are better
    substrates his frequency work.

    It's hard to keep up decent impedances on stripline in a multilayer
    board, especially 8 or 10 layers.

    Stripline is buried between two ground planes. The only tricky part of
    impedance control is the thickness of the dielectric in the two layers
    above and below the strip-line. In a ten layer board this is thinner
    than it would be in a board with fewer layers.

    And eventually the trace has to be skinnier than PCB houses are
    willing to etch.

    Why?

    Run the Saturn program. More layers make the dielectrics thinner, so
    to maintain a useful impedance the traces have to get narrower.

    10 layers gets nasty.




    Standard pricing seems to be around 5 or maybe 4 mils
    width these days. We do a lot of 5, to sneak between BGA balls, but
    sometimes even 5 is too big.

    Thin dielectrics have tolerance issues too. I'm talking about real
    PCBs here, not ideal theoretical stuff.

    Printed circuit board are always real.

    Exactly.


    Pay enough for close-tolerance substrates in the two relevant layers and >>> you should be okay.

    "Pay enough" can get crazy fast. I don't want to pay hundreds of
    dollars for a smallish PCB.

    An eight or ten layer PCB isn't going to be small. You only need lots of >layers when you have to connect lots of stuff.
    https://www.wevolver.com/article/stripline-vs-microstrip

    I wonder if anyone has added surface-mount Heaviside loading coils to >>>>>> a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    It would be a bit silly.

    John snipped the rest of that senstence, without marking the snip.

    You can make lumped constant transmission lines by linking a
    series >>>> of capacitors with discrete inductors, if you want a high >impedance >>>> transmission line - people sold them as thick film hybrid
    assemblies, and I even used a few, a very long time ago.

    Most ideas seem silly to people who are by nature hostile to ideas.

    Not a problem I've got.

    Dismissing is easier than thinking.

    Thinking about what a loading coil might be doing to the impedance of a
    PCB trace isn't something that you seem to have managed to do.

    I certainly had the idea.

    In a remarkably half-baked way.

    Ideas start out fuzzy, or at least they should. I tell my kids, stay
    confused for a while.


    I might Spice a bunch of ltlines with
    inductors between, just for fun. It's unlikely that I'd use such an
    arrangement in real life, but it's just possible, especially if analog
    quality of a fast edge matters, like in a laser modulator maybe. It's
    preferable to just keep all the traces very short, but that's not
    always possible.

    You seem to be intent on re-inventing the lumped constant delay line,
    without being aware that they were commercially available some thirty
    years ago, back when I used them. They may still be available.

    The Tek 545 30 MHz scope had a gigantic, lumped, tunable, differential
    delay line up to the CRT, so you could see the edge that you triggered
    on.

    https://w140.com/tekwiki/images/thumb/1/10/Tek_545a_delay_close.jpg/231px-Tek_545a_delay_close.jpg

    A lossy pcb trace with periodic loading coils is not a lumped-constant
    tx line. In fact, lumped lines are nasty. The number of sections goes
    as Td/Tr squared, which can get awkward fast.

    Meander-line sections connected by loading coils could be interesting.
    One product that I'm considering now is a programmable delay line, and
    that idea might help.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to john larkin on Sat Aug 31 22:52:08 2024
    On 8/31/24 21:31, john larkin wrote:
    On Sun, 1 Sep 2024 02:37:22 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 1/09/2024 12:18 am, john larkin wrote:
    On Sat, 31 Aug 2024 16:17:39 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 31/08/2024 3:10 am, john larkin wrote:
    On Sat, 31 Aug 2024 01:23:19 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote:

    On 31/08/2024 12:34 am, john larkin wrote:
    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid> >>>>>>> wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main >>>>>>>> At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...

    Funny, I just delivered a lecture on transmission lines and noted that >>>>>>> microstrips have dispersion from the unbalanced dielectric constants >>>>>>> and skin effect. Rising edges get sloppy at the and of a long trace. >>>>>>
    I hope you pointed out that buried strip-line isn't dispersive. I have >>>>>> pointed this out here from time to time.

    Of course it's dispersive, maybe a bit less than microstrip.

    Why do you think that?

    Because dielectrics are imperfect, especially FR4, and because there
    are lots of papers online that analyze dispersion in stripline.

    But you can't cite any of them.

    Can't you google?


    You wouldn't use FR4 around a stripline
    if you wanted a low-dispersion transmission line. There are better
    substrates his frequency work.

    It's hard to keep up decent impedances on stripline in a multilayer
    board, especially 8 or 10 layers.

    Stripline is buried between two ground planes. The only tricky part of >>>> impedance control is the thickness of the dielectric in the two layers >>>> above and below the strip-line. In a ten layer board this is thinner
    than it would be in a board with fewer layers.

    And eventually the trace has to be skinnier than PCB houses are
    willing to etch.

    Why?

    Run the Saturn program. More layers make the dielectrics thinner, so
    to maintain a useful impedance the traces have to get narrower.

    10 layers gets nasty.




    Standard pricing seems to be around 5 or maybe 4 mils
    width these days. We do a lot of 5, to sneak between BGA balls, but
    sometimes even 5 is too big.

    Thin dielectrics have tolerance issues too. I'm talking about real
    PCBs here, not ideal theoretical stuff.

    Printed circuit board are always real.

    Exactly.


    Pay enough for close-tolerance substrates in the two relevant layers and >>>> you should be okay.

    "Pay enough" can get crazy fast. I don't want to pay hundreds of
    dollars for a smallish PCB.

    An eight or ten layer PCB isn't going to be small. You only need lots of
    layers when you have to connect lots of stuff.
    https://www.wevolver.com/article/stripline-vs-microstrip

    I wonder if anyone has added surface-mount Heaviside loading coils to >>>>>>> a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    It would be a bit silly.

    John snipped the rest of that senstence, without marking the snip.

    You can make lumped constant transmission lines by linking a
    series >>>> of capacitors with discrete inductors, if you want a high
    impedance >>>> transmission line - people sold them as thick film hybrid >>>>>> assemblies, and I even used a few, a very long time ago.

    Most ideas seem silly to people who are by nature hostile to ideas.

    Not a problem I've got.

    Dismissing is easier than thinking.

    Thinking about what a loading coil might be doing to the impedance of a >>>> PCB trace isn't something that you seem to have managed to do.

    I certainly had the idea.

    In a remarkably half-baked way.

    Ideas start out fuzzy, or at least they should. I tell my kids, stay
    confused for a while.


    I might Spice a bunch of ltlines with
    inductors between, just for fun. It's unlikely that I'd use such an
    arrangement in real life, but it's just possible, especially if analog
    quality of a fast edge matters, like in a laser modulator maybe. It's
    preferable to just keep all the traces very short, but that's not
    always possible.

    You seem to be intent on re-inventing the lumped constant delay line,
    without being aware that they were commercially available some thirty
    years ago, back when I used them. They may still be available.

    The Tek 545 30 MHz scope had a gigantic, lumped, tunable, differential
    delay line up to the CRT, so you could see the edge that you triggered
    on.

    https://w140.com/tekwiki/images/thumb/1/10/Tek_545a_delay_close.jpg/231px-Tek_545a_delay_close.jpg

    A lossy pcb trace with periodic loading coils is not a lumped-constant
    tx line. In fact, lumped lines are nasty. The number of sections goes
    as Td/Tr squared, which can get awkward fast.

    Meander-line sections connected by loading coils could be interesting.
    One product that I'm considering now is a programmable delay line, and
    that idea might help.




    In the 1980's we had NIM-format boxes with binary-weighted-length cables
    and cheap slide switches, and CAMAC modules with basically the same
    cables, but with fancy miniature DPDT relays in metal TO-8 style
    packages. Physicists would invariably mess up the relay contacts.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to jeroen@nospam.please on Sat Aug 31 16:32:29 2024
    On Sat, 31 Aug 2024 22:52:08 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 8/31/24 21:31, john larkin wrote:
    On Sun, 1 Sep 2024 02:37:22 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 1/09/2024 12:18 am, john larkin wrote:
    On Sat, 31 Aug 2024 16:17:39 +1000, Bill Sloman <bill.sloman@ieee.org> >>>> wrote:

    On 31/08/2024 3:10 am, john larkin wrote:
    On Sat, 31 Aug 2024 01:23:19 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>> wrote:

    On 31/08/2024 12:34 am, john larkin wrote:
    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid> >>>>>>>> wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main
    At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...

    Funny, I just delivered a lecture on transmission lines and noted that >>>>>>>> microstrips have dispersion from the unbalanced dielectric constants >>>>>>>> and skin effect. Rising edges get sloppy at the and of a long trace. >>>>>>>
    I hope you pointed out that buried strip-line isn't dispersive. I have >>>>>>> pointed this out here from time to time.

    Of course it's dispersive, maybe a bit less than microstrip.

    Why do you think that?

    Because dielectrics are imperfect, especially FR4, and because there
    are lots of papers online that analyze dispersion in stripline.

    But you can't cite any of them.

    Can't you google?


    You wouldn't use FR4 around a stripline
    if you wanted a low-dispersion transmission line. There are better
    substrates his frequency work.

    It's hard to keep up decent impedances on stripline in a multilayer >>>>>> board, especially 8 or 10 layers.

    Stripline is buried between two ground planes. The only tricky part of >>>>> impedance control is the thickness of the dielectric in the two layers >>>>> above and below the strip-line. In a ten layer board this is thinner >>>>> than it would be in a board with fewer layers.

    And eventually the trace has to be skinnier than PCB houses are
    willing to etch.

    Why?

    Run the Saturn program. More layers make the dielectrics thinner, so
    to maintain a useful impedance the traces have to get narrower.

    10 layers gets nasty.




    Standard pricing seems to be around 5 or maybe 4 mils
    width these days. We do a lot of 5, to sneak between BGA balls, but
    sometimes even 5 is too big.

    Thin dielectrics have tolerance issues too. I'm talking about real
    PCBs here, not ideal theoretical stuff.

    Printed circuit board are always real.

    Exactly.


    Pay enough for close-tolerance substrates in the two relevant layers and >>>>> you should be okay.

    "Pay enough" can get crazy fast. I don't want to pay hundreds of
    dollars for a smallish PCB.

    An eight or ten layer PCB isn't going to be small. You only need lots of >>> layers when you have to connect lots of stuff.
    https://www.wevolver.com/article/stripline-vs-microstrip

    I wonder if anyone has added surface-mount Heaviside loading coils to >>>>>>>> a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    It would be a bit silly.

    John snipped the rest of that senstence, without marking the snip.

    You can make lumped constant transmission lines by linking a
    series >>>> of capacitors with discrete inductors, if you want a high
    impedance >>>> transmission line - people sold them as thick film hybrid >>>>>>> assemblies, and I even used a few, a very long time ago.

    Most ideas seem silly to people who are by nature hostile to ideas. >>>>>
    Not a problem I've got.

    Dismissing is easier than thinking.

    Thinking about what a loading coil might be doing to the impedance of a >>>>> PCB trace isn't something that you seem to have managed to do.

    I certainly had the idea.

    In a remarkably half-baked way.

    Ideas start out fuzzy, or at least they should. I tell my kids, stay
    confused for a while.


    I might Spice a bunch of ltlines with
    inductors between, just for fun. It's unlikely that I'd use such an
    arrangement in real life, but it's just possible, especially if analog >>>> quality of a fast edge matters, like in a laser modulator maybe. It's
    preferable to just keep all the traces very short, but that's not
    always possible.

    You seem to be intent on re-inventing the lumped constant delay line,
    without being aware that they were commercially available some thirty
    years ago, back when I used them. They may still be available.

    The Tek 545 30 MHz scope had a gigantic, lumped, tunable, differential
    delay line up to the CRT, so you could see the edge that you triggered
    on.

    https://w140.com/tekwiki/images/thumb/1/10/Tek_545a_delay_close.jpg/231px-Tek_545a_delay_close.jpg

    A lossy pcb trace with periodic loading coils is not a lumped-constant
    tx line. In fact, lumped lines are nasty. The number of sections goes
    as Td/Tr squared, which can get awkward fast.

    Meander-line sections connected by loading coils could be interesting.
    One product that I'm considering now is a programmable delay line, and
    that idea might help.




    In the 1980's we had NIM-format boxes with binary-weighted-length cables
    and cheap slide switches, and CAMAC modules with basically the same
    cables, but with fancy miniature DPDT relays in metal TO-8 style
    packages. Physicists would invariably mess up the relay contacts.

    Jeroen Belleman

    I was thinking of using the cute little $1 Fujitsu telecom relays,
    which are good up to about 3 GHz.

    https://www.dropbox.com/scl/fi/bvcnqnvb4euc7pqw7wzab/DSC06884.JPG?rlkey=q1op81z1bumkfxoq8d5mtzi91&raw=1

    I don't know if anyone would buy a PoE switched delay line box, but it
    would be fun. Isola has some pretty good PCB laminates that aren't
    expensive like the exotic Rogers stuff.

    I never did any NIM, but we did a bunch of CAMAC. It was a strange
    bus, 24 bits of open-drain read data and a separate 24 bits of write
    data. Design by physicists!

    But the geographical addressing was great. Too bad VME didn't do that.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Sun Sep 1 15:34:13 2024
    On 1/09/2024 5:31 am, john larkin wrote:
    On Sun, 1 Sep 2024 02:37:22 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 1/09/2024 12:18 am, john larkin wrote:
    On Sat, 31 Aug 2024 16:17:39 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 31/08/2024 3:10 am, john larkin wrote:
    On Sat, 31 Aug 2024 01:23:19 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote:

    On 31/08/2024 12:34 am, john larkin wrote:
    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid> >>>>>>> wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main >>>>>>>> At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...

    Funny, I just delivered a lecture on transmission lines and noted that >>>>>>> microstrips have dispersion from the unbalanced dielectric constants >>>>>>> and skin effect. Rising edges get sloppy at the and of a long trace. >>>>>>
    I hope you pointed out that buried strip-line isn't dispersive. I have >>>>>> pointed this out here from time to time.

    Of course it's dispersive, maybe a bit less than microstrip.

    Why do you think that?

    Because dielectrics are imperfect, especially FR4, and because there
    are lots of papers online that analyze dispersion in stripline.

    But you can't cite any of them.

    Can't you google?

    Can't you? You know where you found the papers (if you did) and are much
    better placed to define the search terms that would throw them up.

    You wouldn't use FR4 around a stripline
    if you wanted a low-dispersion transmission line. There are better
    substrates his frequency work.

    It's hard to keep up decent impedances on stripline in a multilayer
    board, especially 8 or 10 layers.

    Stripline is buried between two ground planes. The only tricky part of >>>> impedance control is the thickness of the dielectric in the two layers >>>> above and below the strip-line. In a ten layer board this is thinner
    than it would be in a board with fewer layers.

    And eventually the trace has to be skinnier than PCB houses are
    willing to etch.

    Why?

    Run the Saturn program. More layers make the dielectrics thinner, so
    to maintain a useful impedance the traces have to get narrower.

    I can do that with a handheld calculator. What you seem, to have missed
    is that low dielectric constant substrates give you wider traces for a
    given impedance. I got a 150R line on the surface of teflon-alumina
    substrate.

    10 layers gets nasty.

    If you don't think about what you are doing.

    Standard pricing seems to be around 5 or maybe 4 mils
    width these days. We do a lot of 5, to sneak between BGA balls, but
    sometimes even 5 is too big.

    Thin dielectrics have tolerance issues too. I'm talking about real
    PCBs here, not ideal theoretical stuff.

    Printed circuit board are always real.

    Exactly.

    Pay enough for close-tolerance substrates in the two relevant layers and >>>> you should be okay.

    "Pay enough" can get crazy fast. I don't want to pay hundreds of
    dollars for a smallish PCB.

    An eight or ten layer PCB isn't going to be small. You only need lots of
    layers when you have to connect lots of stuff.

    https://www.wevolver.com/article/stripline-vs-microstrip

    I wonder if anyone has added surface-mount Heaviside loading coils to >>>>>>> a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    It would be a bit silly.

    John snipped the rest of that sentence, without marking the snip.

    You can make lumped constant transmission lines by linking a
    series of capacitors with discrete inductors, if you want a high
    impedance transmission line - people sold them as thick film hybrid >>>>>> assemblies, and I even used a few, a very long time ago.

    Most ideas seem silly to people who are by nature hostile to ideas.

    Not a problem I've got.

    Dismissing is easier than thinking.

    Thinking about what a loading coil might be doing to the impedance of a >>>> PCB trace isn't something that you seem to have managed to do.

    I certainly had the idea.

    In a remarkably half-baked way.

    Ideas start out fuzzy, or at least they should. I tell my kids, stay
    confused for a while.

    You seem to have chosen to stay confused for decades.

    I might Spice a bunch of ltlines with
    inductors between, just for fun. It's unlikely that I'd use such an
    arrangement in real life, but it's just possible, especially if analog
    quality of a fast edge matters, like in a laser modulator maybe. It's
    preferable to just keep all the traces very short, but that's not
    always possible.

    You seem to be intent on re-inventing the lumped constant delay line,
    without being aware that they were commercially available some thirty
    years ago, back when I used them. They may still be available.

    The Tek 545 30 MHz scope had a gigantic, lumped, tunable, differential
    delay line up to the CRT, so you could see the edge that you triggered
    on.

    https://w140.com/tekwiki/images/thumb/1/10/Tek_545a_delay_close.jpg/231px-Tek_545a_delay_close.jpg

    A lossy pcb trace with periodic loading coils is not a lumped-constant
    tx line.

    The discrete loading coils are lumped elements.

    In fact, lumped lines are nasty. The number of sections goes
    as Td/Tr squared, which can get awkward fast.

    All true, which doesn't make them any less useful.

    Meander-line sections connected by loading coils could be interesting.
    One product that I'm considering now is a programmable delay line, and
    that idea might help.

    Like the MC100EP195?

    https://www.onsemi.com/pdf/datasheet/mc100ep195-d.pdf

    You do seem to spend a lot of time re-inventing the wheel, and
    congratulating yourself on the originality of your re-invented concepts.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Sun Sep 1 07:27:30 2024
    On Sun, 1 Sep 2024 15:34:13 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    Meander-line sections connected by loading coils could be interesting.
    One product that I'm considering now is a programmable delay line, and
    that idea might help.

    Like the MC100EP195?

    https://www.onsemi.com/pdf/datasheet/mc100ep195-d.pdf

    You do seem to spend a lot of time re-inventing the wheel, and
    congratulating yourself on the originality of your re-invented concepts.

    I've tested that part. It's expensive, drifty, and has an insane
    amount of jitter. It's funny that its resolution is "about 10 ps"

    Maxim and I think someone else made CMOS programmable delay line
    chips, which were equally bad, not to mention discontinued.

    We mostly use fast ramps and comparators and DACs to make programmable
    delays. Jitter is low and polynomial calibration makes them very
    accurate. Cheap too.

    Of course I keep inventing things. That's my job.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Mon Sep 2 01:24:18 2024
    On 2/09/2024 12:27 am, john larkin wrote:
    On Sun, 1 Sep 2024 15:34:13 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    Meander-line sections connected by loading coils could be interesting.
    One product that I'm considering now is a programmable delay line, and
    that idea might help.

    Like the MC100EP195?

    https://www.onsemi.com/pdf/datasheet/mc100ep195-d.pdf

    You do seem to spend a lot of time re-inventing the wheel, and
    congratulating yourself on the originality of your re-invented concepts.

    I've tested that part. It's expensive, drifty, and has an insane
    amount of jitter. It's funny that its resolution is "about 10 ps"

    It's resolution is about 10psec, because that's the - temperature
    dependent - delay through individual delay elements. If you want it to
    be more precise, you have to control the part's temperature, or
    re-calibrate every few minutes. That's what I was planning to do when I contemplated using it, and figured that I could get it done within a millisecond - which did call for a fast A/D. Which one I can't remember
    because it was back in 1998.

    The RMS random clock jitter is specified on page 10 of the data sheet,
    and it's around 1psec which pretty standard for ECL parts - not remotely insane.

    The nice thing about ECL is that it doesn't mess up it's power rails in
    the way that CMOS and TTL do, which does get rid of one jitter source.

    I once got rid of some nasty sub-nanosecond jitter on a TTL clock by
    generating it in ECL (run between 0V and -4.5V) and getting it
    out of an ECL-to-TTL converter.

    I had expected the ECL-to-TTL converter to be equally susceptible to
    noise on the +5V rail, but I was happy to find out that I was wrong.

    --
    Bill Sloman, Sydney

    Maxim and I think someone else made CMOS programmable delay line
    chips, which were equally bad, not to mention discontinued.

    The MC100EP195 and MC100EP196 have been around for thirty years now, and
    don't seem to have been discontinued.

    We mostly use fast ramps and comparators and DACs to make programmable delays. Jitter is low and polynomial calibration makes them very
    accurate. Cheap too.

    Been there, done that.

    Of course I keep inventing things. That's my job.

    You'd have to do it less often if you knew more about what was already available, and were more skilled at reading the datasheets for the
    stuff you could buy.

    Inventing stuff is fun, but nobody sane does it when they don't have to.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Sun Sep 1 09:32:37 2024
    On Mon, 2 Sep 2024 01:24:18 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 2/09/2024 12:27 am, john larkin wrote:
    On Sun, 1 Sep 2024 15:34:13 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    Meander-line sections connected by loading coils could be interesting. >>>> One product that I'm considering now is a programmable delay line, and >>>> that idea might help.

    Like the MC100EP195?

    https://www.onsemi.com/pdf/datasheet/mc100ep195-d.pdf

    You do seem to spend a lot of time re-inventing the wheel, and
    congratulating yourself on the originality of your re-invented concepts.

    I've tested that part. It's expensive, drifty, and has an insane
    amount of jitter. It's funny that its resolution is "about 10 ps"

    Monotonicity is TBD! It should say "Fat Chance."

    Our ramp delay generators are absolutely monotonic.



    It's resolution is about 10psec, because that's the - temperature
    dependent - delay through individual delay elements. If you want it to
    be more precise, you have to control the part's temperature, or
    re-calibrate every few minutes. That's what I was planning to do when I >contemplated using it, and figured that I could get it done within a >millisecond - which did call for a fast A/D. Which one I can't remember >because it was back in 1998.

    Temperature control, and periodic recalibration, are not practical in
    a sensible instrument. What do you do if the customer makes a trigger
    when you're in the middle of calibrating? Blow up their laser?

    We calibrate delay generators in production test, and they work fine
    after that.


    The RMS random clock jitter is specified on page 10 of the data sheet,
    and it's around 1psec which pretty standard for ECL parts - not remotely >insane.


    I measured a lot more. And the horrible delay tempco is essentially
    jitter, as far as a customer is concerned.



    The nice thing about ECL is that it doesn't mess up it's power rails in
    the way that CMOS and TTL do, which does get rid of one jitter source.

    I once got rid of some nasty sub-nanosecond jitter on a TTL clock by >generating it in ECL (run between 0V and -4.5V) and getting it
    out of an ECL-to-TTL converter.

    I had expected the ECL-to-TTL converter to be equally susceptible to
    noise on the +5V rail, but I was happy to find out that I was wrong.

    The Moto ECL-TTL converters, like the 10H125 or the ELT21, were slow
    and expensive and had ghastly jitter. The Arizona Microtek part is
    better but still pretty bad.

    An LVDS line receiver is cheap and hugely better.



    --
    Bill Sloman, Sydney

    Maxim and I think someone else made CMOS programmable delay line
    chips, which were equally bad, not to mention discontinued.

    The MC100EP195 and MC100EP196 have been around for thirty years now, and >don't seem to have been discontinued.

    We mostly use fast ramps and comparators and DACs to make programmable
    delays. Jitter is low and polynomial calibration makes them very
    accurate. Cheap too.

    Been there, done that.

    Of course I keep inventing things. That's my job.

    You'd have to do it less often if you knew more about what was already >available, and were more skilled at reading the datasheets for the
    stuff you could buy.

    Inventing stuff is fun, but nobody sane does it when they don't have to.

    I never claimed to be sane. Sane is boring. I do claim to design and
    sell a lot of electronics.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to jeroen@nospam.please on Sun Sep 1 11:49:49 2024
    On Sun, 1 Sep 2024 20:37:29 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    In the 1980's we had NIM-format boxes with binary-weighted-length cables >>> and cheap slide switches, and CAMAC modules with basically the same
    cables, but with fancy miniature DPDT relays in metal TO-8 style
    packages. Physicists would invariably mess up the relay contacts.

    Jeroen Belleman

    I was thinking of using the cute little $1 Fujitsu telecom relays,
    which are good up to about 3 GHz.

    https://www.dropbox.com/scl/fi/bvcnqnvb4euc7pqw7wzab/DSC06884.JPG?rlkey=q1op81z1bumkfxoq8d5mtzi91&raw=1

    I don't know if anyone would buy a PoE switched delay line box, but it
    would be fun. Isola has some pretty good PCB laminates that aren't
    expensive like the exotic Rogers stuff.

    I never did any NIM, but we did a bunch of CAMAC. It was a strange
    bus, 24 bits of open-drain read data and a separate 24 bits of write
    data. Design by physicists!

    But the geographical addressing was great. Too bad VME didn't do that.


    The modules I mentioned had coiled-up coax inside. You can't
    squeeze much delay into PCB traces. I've come to think of
    32ns as a really long time...

    A delay box could be a hybrid, some coiled-up coaxes and some PCB
    wiggle traces.


    I used to spend most of my time with CAMAC in the 1980s, but I
    haven't touched it since more than 30 years. It was a weird and
    wasteful bus system, but lots of physics experiments used it at
    the time.

    NIM was simple and stupid. Just a crate with sturdy power supply
    connectors in the back, with +/-6, +/-12 and +/-24V supplies.
    There was more, but no one ever used that. Crates with lots of
    analog would always exceed the current available on the +/-12V,
    and for I/O, you were on your own. Other than that, it was handy
    because it was everywhere. It's still used at CERN, whereas CAMAC
    has vanished. Simple is better.

    Jeroen Belleman

    We invented this for aerospace test

    https://highlandtechnology.com/Category/MPS

    but there's no reason it couldn't be a NIM/CAMAC sort of thing, given
    the right modules.

    PCI/PXI boards don't have the panel space, power, or cooling to do
    serious stuff.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to john larkin on Sun Sep 1 20:37:29 2024
    On 9/1/24 01:32, john larkin wrote:
    On Sat, 31 Aug 2024 22:52:08 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 8/31/24 21:31, john larkin wrote:
    On Sun, 1 Sep 2024 02:37:22 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 1/09/2024 12:18 am, john larkin wrote:
    On Sat, 31 Aug 2024 16:17:39 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote:

    On 31/08/2024 3:10 am, john larkin wrote:
    On Sat, 31 Aug 2024 01:23:19 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>>> wrote:

    On 31/08/2024 12:34 am, john larkin wrote:
    On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid> >>>>>>>>> wrote:

    NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth
    and behaves in some unexpected ways that could have strange consequences for communication on the planet.
    https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main
    At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state,"
    the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) faster than the low-frequency ones.
    That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you would hear the lower-pitched ones.

    paper:
    https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf

    So...
    Music from far away may sound funny?

    For Mars we will need compensation headphones with distance measurement and variable delays....
    ;-)

    Better use radio.. and earplugs/ headphones...

    Funny, I just delivered a lecture on transmission lines and noted that
    microstrips have dispersion from the unbalanced dielectric constants >>>>>>>>> and skin effect. Rising edges get sloppy at the and of a long trace. >>>>>>>>
    I hope you pointed out that buried strip-line isn't dispersive. I have >>>>>>>> pointed this out here from time to time.

    Of course it's dispersive, maybe a bit less than microstrip.

    Why do you think that?

    Because dielectrics are imperfect, especially FR4, and because there >>>>> are lots of papers online that analyze dispersion in stripline.

    But you can't cite any of them.

    Can't you google?


    You wouldn't use FR4 around a stripline
    if you wanted a low-dispersion transmission line. There are better
    substrates his frequency work.

    It's hard to keep up decent impedances on stripline in a multilayer >>>>>>> board, especially 8 or 10 layers.

    Stripline is buried between two ground planes. The only tricky part of >>>>>> impedance control is the thickness of the dielectric in the two layers >>>>>> above and below the strip-line. In a ten layer board this is thinner >>>>>> than it would be in a board with fewer layers.

    And eventually the trace has to be skinnier than PCB houses are
    willing to etch.

    Why?

    Run the Saturn program. More layers make the dielectrics thinner, so
    to maintain a useful impedance the traces have to get narrower.

    10 layers gets nasty.




    Standard pricing seems to be around 5 or maybe 4 mils
    width these days. We do a lot of 5, to sneak between BGA balls, but
    sometimes even 5 is too big.

    Thin dielectrics have tolerance issues too. I'm talking about real
    PCBs here, not ideal theoretical stuff.

    Printed circuit board are always real.

    Exactly.


    Pay enough for close-tolerance substrates in the two relevant layers and >>>>>> you should be okay.

    "Pay enough" can get crazy fast. I don't want to pay hundreds of
    dollars for a smallish PCB.

    An eight or ten layer PCB isn't going to be small. You only need lots of >>>> layers when you have to connect lots of stuff.
    https://www.wevolver.com/article/stripline-vs-microstrip

    I wonder if anyone has added surface-mount Heaviside loading coils to >>>>>>>>> a PCB trace.

    https://en.wikipedia.org/wiki/Loading_coil

    It would be a bit silly.

    John snipped the rest of that senstence, without marking the snip.

    You can make lumped constant transmission lines by linking a
    series >>>> of capacitors with discrete inductors, if you want a high
    impedance >>>> transmission line - people sold them as thick film hybrid >>>>>>>> assemblies, and I even used a few, a very long time ago.

    Most ideas seem silly to people who are by nature hostile to ideas. >>>>>>
    Not a problem I've got.

    Dismissing is easier than thinking.

    Thinking about what a loading coil might be doing to the impedance of a >>>>>> PCB trace isn't something that you seem to have managed to do.

    I certainly had the idea.

    In a remarkably half-baked way.

    Ideas start out fuzzy, or at least they should. I tell my kids, stay
    confused for a while.


    I might Spice a bunch of ltlines with
    inductors between, just for fun. It's unlikely that I'd use such an
    arrangement in real life, but it's just possible, especially if analog >>>>> quality of a fast edge matters, like in a laser modulator maybe. It's >>>>> preferable to just keep all the traces very short, but that's not
    always possible.

    You seem to be intent on re-inventing the lumped constant delay line,
    without being aware that they were commercially available some thirty
    years ago, back when I used them. They may still be available.

    The Tek 545 30 MHz scope had a gigantic, lumped, tunable, differential
    delay line up to the CRT, so you could see the edge that you triggered
    on.

    https://w140.com/tekwiki/images/thumb/1/10/Tek_545a_delay_close.jpg/231px-Tek_545a_delay_close.jpg

    A lossy pcb trace with periodic loading coils is not a lumped-constant
    tx line. In fact, lumped lines are nasty. The number of sections goes
    as Td/Tr squared, which can get awkward fast.

    Meander-line sections connected by loading coils could be interesting.
    One product that I'm considering now is a programmable delay line, and
    that idea might help.




    In the 1980's we had NIM-format boxes with binary-weighted-length cables
    and cheap slide switches, and CAMAC modules with basically the same
    cables, but with fancy miniature DPDT relays in metal TO-8 style
    packages. Physicists would invariably mess up the relay contacts.

    Jeroen Belleman

    I was thinking of using the cute little $1 Fujitsu telecom relays,
    which are good up to about 3 GHz.

    https://www.dropbox.com/scl/fi/bvcnqnvb4euc7pqw7wzab/DSC06884.JPG?rlkey=q1op81z1bumkfxoq8d5mtzi91&raw=1

    I don't know if anyone would buy a PoE switched delay line box, but it
    would be fun. Isola has some pretty good PCB laminates that aren't
    expensive like the exotic Rogers stuff.

    I never did any NIM, but we did a bunch of CAMAC. It was a strange
    bus, 24 bits of open-drain read data and a separate 24 bits of write
    data. Design by physicists!

    But the geographical addressing was great. Too bad VME didn't do that.


    The modules I mentioned had coiled-up coax inside. You can't
    squeeze much delay into PCB traces. I've come to think of
    32ns as a really long time...

    I used to spend most of my time with CAMAC in the 1980s, but I
    haven't touched it since more than 30 years. It was a weird and
    wasteful bus system, but lots of physics experiments used it at
    the time.

    NIM was simple and stupid. Just a crate with sturdy power supply
    connectors in the back, with +/-6, +/-12 and +/-24V supplies.
    There was more, but no one ever used that. Crates with lots of
    analog would always exceed the current available on the +/-12V,
    and for I/O, you were on your own. Other than that, it was handy
    because it was everywhere. It's still used at CERN, whereas CAMAC
    has vanished. Simple is better.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Mon Sep 2 18:23:26 2024
    On 2/09/2024 2:32 am, john larkin wrote:
    On Mon, 2 Sep 2024 01:24:18 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 2/09/2024 12:27 am, john larkin wrote:
    On Sun, 1 Sep 2024 15:34:13 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    Meander-line sections connected by loading coils could be interesting. >>>>> One product that I'm considering now is a programmable delay line, and >>>>> that idea might help.

    Like the MC100EP195?

    https://www.onsemi.com/pdf/datasheet/mc100ep195-d.pdf

    You do seem to spend a lot of time re-inventing the wheel, and
    congratulating yourself on the originality of your re-invented concepts. >>>
    I've tested that part. It's expensive, drifty, and has an insane
    amount of jitter. It's funny that its resolution is "about 10 ps"

    Monotonicity is TBD! It should say "Fat Chance."

    Our ramp delay generators are absolutely monotonic.



    It's resolution is about 10psec, because that's the - temperature
    dependent - delay through individual delay elements. If you want it to
    be more precise, you have to control the part's temperature, or
    re-calibrate every few minutes. That's what I was planning to do when I
    contemplated using it, and figured that I could get it done within a
    millisecond - which did call for a fast A/D. Which one I can't remember
    because it was back in 1998.

    Temperature control, and periodic recalibration, are not practical in
    a sensible instrument. What do you do if the customer makes a trigger
    when you're in the middle of calibrating? Blow up their laser?

    We calibrate delay generators in production test, and they work fine
    after that.


    The RMS random clock jitter is specified on page 10 of the data sheet,
    and it's around 1psec which pretty standard for ECL parts - not remotely
    insane.


    I measured a lot more. And the horrible delay tempco is essentially
    jitter, as far as a customer is concerned.



    The nice thing about ECL is that it doesn't mess up it's power rails in
    the way that CMOS and TTL do, which does get rid of one jitter source.

    I once got rid of some nasty sub-nanosecond jitter on a TTL clock by
    generating it in ECL (run between 0V and -4.5V) and getting it
    out of an ECL-to-TTL converter.

    I had expected the ECL-to-TTL converter to be equally susceptible to
    noise on the +5V rail, but I was happy to find out that I was wrong.

    The Moto ECL-TTL converters, like the 10H125 or the ELT21, were slow
    and expensive and had ghastly jitter. The Arizona Microtek part is
    better but still pretty bad.

    As far as I can remember I used a regular Philips 100K ECL-to-TTL
    converter, and it obviously didn't have ghastly jitter. I was careful
    about power rail decoupling, and a ham-fisted half-wit could probably
    have managed to introduce significant jitter. Ran van Dongen, who had
    designed the original almost-all-TTL system, was neither ham-fisted nor
    a half-wit, if a bit less ECL-aware than he should have been. He rather
    liked what I came up with. I mostly used Motorola ECinPS parts which
    hadn't been around when he had designed the original system

    ECL is a low volume product, so it isn't cheap, but when you need it it
    is worth the money.
    An LVDS line receiver is cheap and hugely better.

    But it doesn't produce a TTL output.

    Inventing stuff is fun, but nobody sane does it when they don't have to.

    I never claimed to be sane. Sane is boring. I do claim to design and
    sell a lot of electronics.

    When in fact you evolve and sell a certain amount of electronics for
    niche markets. Your forays into higher volume markets don't seem to have
    done well. You are insane enough to think this gives you some kind of authority.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Mon Sep 2 09:02:56 2024
    On Mon, 2 Sep 2024 18:23:26 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 2/09/2024 2:32 am, john larkin wrote:
    On Mon, 2 Sep 2024 01:24:18 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 2/09/2024 12:27 am, john larkin wrote:
    On Sun, 1 Sep 2024 15:34:13 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    Meander-line sections connected by loading coils could be interesting. >>>>>> One product that I'm considering now is a programmable delay line, and >>>>>> that idea might help.

    Like the MC100EP195?

    https://www.onsemi.com/pdf/datasheet/mc100ep195-d.pdf

    You do seem to spend a lot of time re-inventing the wheel, and
    congratulating yourself on the originality of your re-invented concepts. >>>>
    I've tested that part. It's expensive, drifty, and has an insane
    amount of jitter. It's funny that its resolution is "about 10 ps"

    Monotonicity is TBD! It should say "Fat Chance."

    Our ramp delay generators are absolutely monotonic.



    It's resolution is about 10psec, because that's the - temperature
    dependent - delay through individual delay elements. If you want it to
    be more precise, you have to control the part's temperature, or
    re-calibrate every few minutes. That's what I was planning to do when I
    contemplated using it, and figured that I could get it done within a
    millisecond - which did call for a fast A/D. Which one I can't remember
    because it was back in 1998.

    Temperature control, and periodic recalibration, are not practical in
    a sensible instrument. What do you do if the customer makes a trigger
    when you're in the middle of calibrating? Blow up their laser?

    We calibrate delay generators in production test, and they work fine
    after that.


    The RMS random clock jitter is specified on page 10 of the data sheet,
    and it's around 1psec which pretty standard for ECL parts - not remotely >>> insane.


    I measured a lot more. And the horrible delay tempco is essentially
    jitter, as far as a customer is concerned.



    The nice thing about ECL is that it doesn't mess up it's power rails in
    the way that CMOS and TTL do, which does get rid of one jitter source.

    I once got rid of some nasty sub-nanosecond jitter on a TTL clock by
    generating it in ECL (run between 0V and -4.5V) and getting it
    out of an ECL-to-TTL converter.

    I had expected the ECL-to-TTL converter to be equally susceptible to
    noise on the +5V rail, but I was happy to find out that I was wrong.

    The Moto ECL-TTL converters, like the 10H125 or the ELT21, were slow
    and expensive and had ghastly jitter. The Arizona Microtek part is
    better but still pretty bad.

    As far as I can remember I used a regular Philips 100K ECL-to-TTL
    converter, and it obviously didn't have ghastly jitter. I was careful
    about power rail decoupling, and a ham-fisted half-wit could probably
    have managed to introduce significant jitter. Ran van Dongen, who had >designed the original almost-all-TTL system, was neither ham-fisted nor
    a half-wit, if a bit less ECL-aware than he should have been. He rather
    liked what I came up with. I mostly used Motorola ECinPS parts which
    hadn't been around when he had designed the original system

    ECL is a low volume product, so it isn't cheap, but when you need it it
    is worth the money.
    An LVDS line receiver is cheap and hugely better.

    But it doesn't produce a TTL output.

    DS90LV012ATMF/NOPB is essentially a fast rrio comparator. Its outputs
    swing from ground to Vcc. It costs us 30 cents. If you buy a similar
    part that's called a comparator, it costs 5x as much.

    Like most cmos rrio gadgets, its offset increases as the common-mode
    approaches Vcc, but that's no big deal in a polynomial-calibrated
    ramp.


    Inventing stuff is fun, but nobody sane does it when they don't have to.

    I never claimed to be sane. Sane is boring. I do claim to design and
    sell a lot of electronics.

    When in fact you evolve and sell a certain amount of electronics for
    niche markets. Your forays into higher volume markets don't seem to have
    done well. You are insane enough to think this gives you some kind of >authority.

    I mostly like to design electronics because it's fun and keeps me
    amused. Better than having a real job. People buying it is a nice side
    effect and pays for test equipment and snacks.

    Don't you think designing electronics is amusing? I guess not.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Tue Sep 3 15:48:32 2024
    On 3/09/2024 2:02 am, john larkin wrote:
    On Mon, 2 Sep 2024 18:23:26 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 2/09/2024 2:32 am, john larkin wrote:
    On Mon, 2 Sep 2024 01:24:18 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 2/09/2024 12:27 am, john larkin wrote:
    On Sun, 1 Sep 2024 15:34:13 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote:

    <snip>

    Inventing stuff is fun, but nobody sane does it when they don't have to. >>>
    I never claimed to be sane. Sane is boring. I do claim to design and
    sell a lot of electronics.

    When in fact you evolve and sell a certain amount of electronics for
    niche markets. Your forays into higher volume markets don't seem to have
    done well. You are insane enough to think this gives you some kind of
    authority.

    I mostly like to design electronics because it's fun and keeps me
    amused. Better than having a real job. People buying it is a nice side
    effect and pays for test equipment and snacks.

    Don't you think designing electronics is amusing? I guess not.

    It's certainly fascinating. Having to toss out lots of solutions and
    start over isn't remotely amusing, but that's what it takes to get to a
    good design.

    It has a lot in common with playing colossal cave

    https://en.wikipedia.org/wiki/Colossal_Cave_Adventure

    though with a computer game you can be confident that there is a
    solution, while in real life you may find that you need to move the
    goal-posts, or adjust the client's ambitions.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Wed Sep 4 07:58:18 2024
    On Tue, 3 Sep 2024 15:48:32 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 3/09/2024 2:02 am, john larkin wrote:
    On Mon, 2 Sep 2024 18:23:26 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 2/09/2024 2:32 am, john larkin wrote:
    On Mon, 2 Sep 2024 01:24:18 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 2/09/2024 12:27 am, john larkin wrote:
    On Sun, 1 Sep 2024 15:34:13 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>> wrote:

    <snip>

    Inventing stuff is fun, but nobody sane does it when they don't have to. >>>>
    I never claimed to be sane. Sane is boring. I do claim to design and
    sell a lot of electronics.

    When in fact you evolve and sell a certain amount of electronics for
    niche markets. Your forays into higher volume markets don't seem to have >>> done well. You are insane enough to think this gives you some kind of
    authority.

    I mostly like to design electronics because it's fun and keeps me
    amused. Better than having a real job. People buying it is a nice side
    effect and pays for test equipment and snacks.

    Don't you think designing electronics is amusing? I guess not.

    It's certainly fascinating. Having to toss out lots of solutions and
    start over isn't remotely amusing, but that's what it takes to get to a
    good design.

    But its is very amusing.


    It has a lot in common with playing colossal cave

    https://en.wikipedia.org/wiki/Colossal_Cave_Adventure

    though with a computer game you can be confident that there is a
    solution, while in real life you may find that you need to move the >goal-posts, or adjust the client's ambitions.

    Trying lots of arguably crazy ideas is educational, and has a chance
    of stumbling onto something really valuable. But one has to do it
    fast, because there's literally a universe of possibilities to
    explore.

    Exploring Colossal Cave is a good analogy to exploring the electronic
    circuit solution space, except the circuit space is much bigger hence impossible to explore serially.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Thu Sep 5 15:59:23 2024
    On 5/09/2024 12:58 am, john larkin wrote:
    On Tue, 3 Sep 2024 15:48:32 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 3/09/2024 2:02 am, john larkin wrote:
    On Mon, 2 Sep 2024 18:23:26 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 2/09/2024 2:32 am, john larkin wrote:
    On Mon, 2 Sep 2024 01:24:18 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote:

    On 2/09/2024 12:27 am, john larkin wrote:
    On Sun, 1 Sep 2024 15:34:13 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>>> wrote:

    <snip>

    It has a lot in common with playing colossal cave

    https://en.wikipedia.org/wiki/Colossal_Cave_Adventure

    though with a computer game you can be confident that there is a
    solution, while in real life you may find that you need to move the
    goal-posts, or adjust the client's ambitions.

    Trying lots of arguably crazy ideas is educational, and has a chance
    of stumbling onto something really valuable. But one has to do it
    fast, because there's literally a universe of possibilities to
    explore.

    Exploring Colossal Cave is a good analogy to exploring the electronic
    circuit solution space, except the circuit space is much bigger hence impossible to explore serially.

    Serial implies one-dimensional ordering, while Collossal Cave was two dimensional.

    Most circuit problems have a single input and single output, but the
    space in between can be as complicated as you like.

    If the problem you are trying to solve has conventional solutions, these
    can serve as known routes through the territory you need to explore, and
    I've had people reject my short-cuts because they didn't understand the
    problem clearly enough.

    --
    Bill Sloman, Sydne

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Thu Sep 5 15:58:47 2024
    On 5/09/2024 12:58 am, john larkin wrote:
    On Tue, 3 Sep 2024 15:48:32 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 3/09/2024 2:02 am, john larkin wrote:
    On Mon, 2 Sep 2024 18:23:26 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 2/09/2024 2:32 am, john larkin wrote:
    On Mon, 2 Sep 2024 01:24:18 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote:

    On 2/09/2024 12:27 am, john larkin wrote:
    On Sun, 1 Sep 2024 15:34:13 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>>> wrote:

    <snip>

    It has a lot in common with playing colossal cave

    https://en.wikipedia.org/wiki/Colossal_Cave_Adventure

    though with a computer game you can be confident that there is a
    solution, while in real life you may find that you need to move the
    goal-posts, or adjust the client's ambitions.

    Trying lots of arguably crazy ideas is educational, and has a chance
    of stumbling onto something really valuable. But one has to do it
    fast, because there's literally a universe of possibilities to
    explore.

    Exploring Colossal Cave is a good analogy to exploring the electronic
    circuit solution space, except the circuit space is much bigger hence impossible to explore serially.

    Serial implies one-dimensional ordering, while Collossal Cave was two dimensional.

    Most circuit problems have a single input and single output, but the
    space in between can be as complicated as you like.

    If the problem you are trying to solve has conventional solutions, these
    can serve as known routes through the territory you need to explore, and
    I've had people reject my short-cuts because they didn't understand the
    problem clearly enough.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Thu Sep 5 07:19:28 2024
    On Thu, 5 Sep 2024 15:58:47 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 5/09/2024 12:58 am, john larkin wrote:
    On Tue, 3 Sep 2024 15:48:32 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 3/09/2024 2:02 am, john larkin wrote:
    On Mon, 2 Sep 2024 18:23:26 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 2/09/2024 2:32 am, john larkin wrote:
    On Mon, 2 Sep 2024 01:24:18 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>> wrote:

    On 2/09/2024 12:27 am, john larkin wrote:
    On Sun, 1 Sep 2024 15:34:13 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>>>> wrote:

    <snip>

    It has a lot in common with playing colossal cave

    https://en.wikipedia.org/wiki/Colossal_Cave_Adventure

    though with a computer game you can be confident that there is a
    solution, while in real life you may find that you need to move the
    goal-posts, or adjust the client's ambitions.

    Trying lots of arguably crazy ideas is educational, and has a chance
    of stumbling onto something really valuable. But one has to do it
    fast, because there's literally a universe of possibilities to
    explore.

    Exploring Colossal Cave is a good analogy to exploring the electronic
    circuit solution space, except the circuit space is much bigger hence
    impossible to explore serially.

    Serial implies one-dimensional ordering, while Collossal Cave was two >dimensional.

    Most circuit problems have a single input and single output, but the
    space in between can be as complicated as you like.


    The set of all circuits that can be designed from the Digikey catalog
    is past 2-dimensional.

    The trick is to use a good search algorithm.


    If the problem you are trying to solve has conventional solutions, these
    can serve as known routes through the territory you need to explore, and
    I've had people reject my short-cuts because they didn't understand the >problem clearly enough.

    Yes, most people reject unusual solutions for several reasons, one
    being jealousy that they couldn't think of it.

    Conventional solutions will have lots of competitors, who have to
    fight it out by under-bidding one another.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Fri Sep 6 21:52:24 2024
    On 6/09/2024 12:19 am, john larkin wrote:
    On Thu, 5 Sep 2024 15:58:47 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 5/09/2024 12:58 am, john larkin wrote:
    On Tue, 3 Sep 2024 15:48:32 +1000, Bill Sloman <bill.sloman@ieee.org>
    wrote:

    On 3/09/2024 2:02 am, john larkin wrote:
    On Mon, 2 Sep 2024 18:23:26 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote:

    On 2/09/2024 2:32 am, john larkin wrote:
    On Mon, 2 Sep 2024 01:24:18 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>>> wrote:

    On 2/09/2024 12:27 am, john larkin wrote:
    On Sun, 1 Sep 2024 15:34:13 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>>>>> wrote:

    <snip>

    It has a lot in common with playing colossal cave

    https://en.wikipedia.org/wiki/Colossal_Cave_Adventure

    though with a computer game you can be confident that there is a
    solution, while in real life you may find that you need to move the
    goal-posts, or adjust the client's ambitions.

    Trying lots of arguably crazy ideas is educational, and has a chance
    of stumbling onto something really valuable. But one has to do it
    fast, because there's literally a universe of possibilities to
    explore.

    Exploring Colossal Cave is a good analogy to exploring the electronic
    circuit solution space, except the circuit space is much bigger hence
    impossible to explore serially.

    Serial implies one-dimensional ordering, while Collossal Cave was two
    dimensional.

    Most circuit problems have a single input and single output, but the
    space in between can be as complicated as you like.


    The set of all circuits that can be designed from the Digikey catalog
    is past 2-dimensional.

    Obviously.

    The trick is to use a good search algorithm.

    There isn't one. An algorithm is an explicit step-by-step procedure, and
    the process of getting from a client's requirement to a workable design
    doesn't seem to have been systematised to that extent.

    If the problem you are trying to solve has conventional solutions, these
    can serve as known routes through the territory you need to explore, and
    I've had people reject my short-cuts because they didn't understand the
    problem clearly enough.

    Yes, most people reject unusual solutions for several reasons, one
    being jealousy that they couldn't think of it.

    I can't say that I've seen that. The example that I had in mind rejected
    what I'd proposed because it used a little bit of positive feedback and
    that - to him - suggested that it could latch up. It couldn't have and
    never did when Honeywell used it a few years later (not that either of
    us had anything to do with that).

    Conventional solutions will have lots of competitors, who have to
    fight it out by under-bidding one another.

    Obvious solutions tend to get adopted more frequently (which is what
    makes them "conventional"). The cheapest acceptable solution does tend
    to become an industry standard, and about the only way to under-cut that
    kind of competition is by producing the product on a larger scale,
    usually in China.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
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