The recent thread on high-end oscilloscopes has reminded me of a project
that I shelved some years ago and might be due for resurrection: I am looking for a real-time display about 3" x 4" that can behave as an X-Y oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be
ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14"
long, which means it has to be a standalone shelf unit and I can't build anything like it into portable equipment.
I've not come across anything like this, but I'm sure such things either exist or can be made by adapting something that is readily available. I
have never been down the digital route, so anything that would need a
lot of programming from scratch will never get built.
On 28-08-2024 01:09 pm, Liz Tuddenham wrote:
The recent thread on high-end oscilloscopes has reminded me of a project that I shelved some years ago and might be due for resurrection: I am looking for a real-time display about 3" x 4" that can behave as an X-Y oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14"
long, which means it has to be a standalone shelf unit and I can't build anything like it into portable equipment.
I've not come across anything like this, but I'm sure such things either exist or can be made by adapting something that is readily available. I have never been down the digital route, so anything that would need a
lot of programming from scratch will never get built.
How about this? https://tinyurl.com/39pkzb5v
I haven't used this Chinese kit myself but it's been around for quite
some time. The display is only 2.4" though. With an aspect ratio of 4:3,
that would be about 1.9x1.4.
The recent thread on high-end oscilloscopes has reminded me of a project
that I shelved some years ago and might be due for resurrection: I am >looking for a real-time display about 3" x 4" that can behave as an X-Y >oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be
ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14"
long, which means it has to be a standalone shelf unit and I can't build >anything like it into portable equipment.
I've not come across anything like this, but I'm sure such things either >exist or can be made by adapting something that is readily available. I
have never been down the digital route, so anything that would need a
lot of programming from scratch will never get built.
On a sunny day (Wed, 28 Aug 2024 08:39:25 +0100) it happened liz@poppyrecords.invalid.invalid (Liz Tuddenham) wrote in <1qyzrl3.ocj6lm4e4yaN%liz@poppyrecords.invalid.invalid>:
The recent thread on high-end oscilloscopes has reminded me of a project >that I shelved some years ago and might be due for resurrection: I am >looking for a real-time display about 3" x 4" that can behave as an X-Y >oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be >ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14"
long, which means it has to be a standalone shelf unit and I can't build >anything like it into portable equipment.
I've not come across anything like this, but I'm sure such things either >exist or can be made by adapting something that is readily available. I >have never been down the digital route, so anything that would need a lot >of programming from scratch will never get built.
This was an experiment:
https://panteltje.nl/panteltje/pic/scope_pic/
works for audio, has spectral display too,
can also send screendump as text file to Usenet.
Control via RS232 or some buttons if you can code.
Cost? Maybe the LCD is the most expensive part, 5 dollars?
Display has low resolution, so I did a shift right a couple of times to divide the output. A better display will give better resolution.
There are plenty of single chip cheap digital scopes on ebay.
https://www.ebay.nl/itm/315279795435
have not tried that one :-)
The recent thread on high-end oscilloscopes has reminded me of a project
that I shelved some years ago and might be due for resurrection: I am looking for a real-time display about 3" x 4" that can behave as an X-Y oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be
ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14"
long, which means it has to be a standalone shelf unit and I can't build anything like it into portable equipment.
I've not come across anything like this, but I'm sure such things either exist or can be made by adapting something that is readily available. I
have never been down the digital route, so anything that would need a
lot of programming from scratch will never get built.
Jan Panteltje <alien@comet.invalid> wrote:
On a sunny day (Wed, 28 Aug 2024 08:39:25 +0100) it happened
liz@poppyrecords.invalid.invalid (Liz Tuddenham) wrote in
<1qyzrl3.ocj6lm4e4yaN%liz@poppyrecords.invalid.invalid>:
The recent thread on high-end oscilloscopes has reminded me of a project
that I shelved some years ago and might be due for resurrection: I am
looking for a real-time display about 3" x 4" that can behave as an X-Y
oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be
ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14"
long, which means it has to be a standalone shelf unit and I can't build
anything like it into portable equipment.
I've not come across anything like this, but I'm sure such things either
exist or can be made by adapting something that is readily available. I
have never been down the digital route, so anything that would need a lot >> >of programming from scratch will never get built.
This was an experiment:
https://panteltje.nl/panteltje/pic/scope_pic/
works for audio, has spectral display too,
can also send screendump as text file to Usenet.
Control via RS232 or some buttons if you can code.
Thanks very much for that. It has most of the reatures I need and the >sampling rate is just about adequate. It 'remembers' its last settings, >which is essential for this application.
I have coded in the past but it was a most frustrating exercise and
something I would like to avoid if possible. Also, I don't have any way
of connecting to the chip and uploading the code.
Cost? Maybe the LCD is the most expensive part, 5 dollars?
Very reasonable
Display has low resolution, so I did a shift right a couple of times to
divide the output. A better display will give better resolution.
The detail is extemenly important in this application - the minimum >resolution being 200 dpi.
There are plenty of single chip cheap digital scopes on ebay.
https://www.ebay.nl/itm/315279795435
have not tried that one :-)
I'll have to work through them and see which ones can be used as X-Y
scopes, with good enough resolution and the ability to start fully
functional from power-up.
Failing that, I have an oscilloscope tube and driver chassis, so I could >mount it horizontally in the bottom of the box with a 45-degree mirror,
so I can look down on it through a hole in the horizontal control panel.
On 28/08/2024 08:39, Liz Tuddenham wrote:
The recent thread on high-end oscilloscopes has reminded me of a project
that I shelved some years ago and might be due for resurrection: I am
looking for a real-time display about 3" x 4" that can behave as an X-Y
oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be
ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14"
long, which means it has to be a standalone shelf unit and I can't build
anything like it into portable equipment.
I think that Daqarta software can probably do about what you want using the PC
stereo soundcard to digitise X & Y. 100kHz bandwidth might be pushing it but it
should be fine for audio up to 20kHz.
On 8/28/2024 7:47 AM, Martin Brown wrote:
On 28/08/2024 08:39, Liz Tuddenham wrote:
The recent thread on high-end oscilloscopes has reminded me of a project >>> that I shelved some years ago and might be due for resurrection: I am
looking for a real-time display about 3" x 4" that can behave as an X-Y
oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be
ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14"
long, which means it has to be a standalone shelf unit and I can't build >>> anything like it into portable equipment.
I think that Daqarta software can probably do about what you want
using the PC stereo soundcard to digitise X & Y. 100kHz bandwidth
might be pushing it but it should be fine for audio up to 20kHz.
Does it *simultaneously* sample each channel? Or, toggle between them?
The advantage would be that you could locate the data acquisition
hardware separately from the (COTS) display.
On 28/08/2024 16:32, Don Y wrote:
On 8/28/2024 7:47 AM, Martin Brown wrote:
On 28/08/2024 08:39, Liz Tuddenham wrote:
The recent thread on high-end oscilloscopes has reminded me of a project >>>> that I shelved some years ago and might be due for resurrection: I am >>>> looking for a real-time display about 3" x 4" that can behave as an X-Y >>>> oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be >>>> ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14" >>>> long, which means it has to be a standalone shelf unit and I can't build >>>> anything like it into portable equipment.
I think that Daqarta software can probably do about what you want using the >>> PC stereo soundcard to digitise X & Y. 100kHz bandwidth might be pushing it >>> but it should be fine for audio up to 20kHz.
Does it *simultaneously* sample each channel? Or, toggle between them?
I have never looked hard enough or at a high enough frequency to tell the difference.
Audio demo's work best around 440Hz orchestral A which most people
can hear well. Waveform shapes and sounds are fun demos.
The guy knows what he is doing so I expect it is simultaneous sampling of the waveforms to within a few memory cycles. Skew only becoming a problem at very high frequencies. It is cute there is a free trial period and you get to keep the (audio) waveform generator.
There is something similar for Android tablet/phones too but I don't think that
one does X-Y Lissajous figures (I could be wrong about that). The waterfall spectrograph is quite a handy toy to have on your phone...
The advantage would be that you could locate the data acquisition
hardware separately from the (COTS) display.
It is a neat piece of software. Every now and then AV codes take against it because it does do a bit of rather low level IO access (obviously).
On 8/28/2024 7:47 AM, Martin Brown wrote:
On 28/08/2024 08:39, Liz Tuddenham wrote:
The recent thread on high-end oscilloscopes has reminded me of a project >>> that I shelved some years ago and might be due for resurrection: I am
looking for a real-time display about 3" x 4" that can behave as an X-Y
oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be
ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14"
long, which means it has to be a standalone shelf unit and I can't build >>> anything like it into portable equipment.
I think that Daqarta software can probably do about what you want using the PC
stereo soundcard to digitise X & Y. 100kHz bandwidth might be pushing it but it
should be fine for audio up to 20kHz.
Does it *simultaneously* sample each channel? Or, toggle between them?
The advantage would be that you could locate the data acquisition
hardware separately from the (COTS) display.
On 2024-08-28, Don Y <blockedofcourse@foo.invalid> wrote:
On 8/28/2024 7:47 AM, Martin Brown wrote:
On 28/08/2024 08:39, Liz Tuddenham wrote:
The recent thread on high-end oscilloscopes has reminded me of a project >>> that I shelved some years ago and might be due for resurrection: I am >>> looking for a real-time display about 3" x 4" that can behave as an X-Y >>> oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be >>> ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14" >>> long, which means it has to be a standalone shelf unit and I can't build >>> anything like it into portable equipment.
I think that Daqarta software can probably do about what you want using
the PC stereo soundcard to digitise X & Y. 100kHz bandwidth might be
pushing it but it should be fine for audio up to 20kHz.
or any other sound card scope software,
Does it *simultaneously* sample each channel? Or, toggle between them?
It makes an audio recording using commodity PC sound hardware. https://www.ti.com/product/PCM2900C has 2 ADC channels
The advantage would be that you could locate the data acquisition
hardware separately from the (COTS) display.
It's starting to feel like raspberry pi + LCD display + usb sound card.
If the Raspberry Pi could be made to fire itself up without any
intervention and accept two analogue inputs, that would work. (...but >someone would have to program it for me, or at least lead me through how
to program it.) The 100Kc/s requirement isn't just fanciful >over-specification; this thing works on the signals that are well
outside the audio band and the 'scope needs to display them clearly,
despite all the audio clutter. The H.F. signals are higher amplitude
than the audio but are in the nature of pulses and occur infrequently.
(The analogue scope has to be Z modulated from rate-of-change to
emphasise the pulses and avoid screen burn, but this wouldn't be a
problem with an LCD display.)
On 29/08/2024 10:43, Liz Tuddenham wrote:
Jasen Betts <usenet@revmaps.no-ip.org> wrote:
On 2024-08-28, Don Y <blockedofcourse@foo.invalid> wrote:
On 8/28/2024 7:47 AM, Martin Brown wrote:
On 28/08/2024 08:39, Liz Tuddenham wrote: > The recent thread on >>>>high-end oscilloscopes has reminded me of a project > that I shelved >>>>some years ago and might be due for resurrection:Â I am > looking >>>>for a real-time display about 3" x 4" that can behave as an X-Y > >>>>oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be >>>>> ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output >>>>> from a stereo gramophone cartridge, which allows me to check historic >>>>> discs for damage or faulty recording geometry. The tube is about 14"
long, which means it has to be a standalone shelf unit and I can't build
anything like it into portable equipment.
I think that Daqarta software can probably do about what you want using >>>> the PC stereo soundcard to digitise X & Y. 100kHz bandwidth might be >>>> pushing it but it should be fine for audio up to 20kHz.
or any other sound card scope software,
Does it *simultaneously* sample each channel? Or, toggle between them? >>It makes an audio recording using commodity PC sound hardware.
https://www.ti.com/product/PCM2900C has 2 ADC channels
The advantage would be that you could locate the data acquisition
hardware separately from the (COTS) display.
It's starting to feel like raspberry pi + LCD display + usb sound card.
The first bit sounds OK apart from the programming. This is a
standalone piece of analogue equipment, so there is no computer, no USB
and no sound card (nor any possibility of them).
If the Raspberry Pi could be made to fire itself up without any intervention and accept two analogue inputs, that would work. (...but someone would have to program it for me, or at least lead me through how
to program it.) The 100Kc/s requirement isn't just fanciful over-specification; this thing works on the signals that are well
outside the audio band and the 'scope needs to display them clearly, despite all the audio clutter. The H.F. signals are higher amplitude
than the audio but are in the nature of pulses and occur infrequently.
(The analogue scope has to be Z modulated from rate-of-change to
emphasise the pulses and avoid screen burn, but this wouldn't be a
problem with an LCD display.)
Something like this on eBay might be what you want then:
https://www.ebay.co.uk/itm/275987222657
10MHz b/w (optimistic but probably better than 2Mhz) X-Y option.
I was assuming every engineer had a spare PC (or ten) lying around.
On a sunny day (Thu, 29 Aug 2024 10:43:29 +0100) it happened liz@poppyrecords.invalid.invalid (Liz Tuddenham) wrote in <1qz1rr1.1p7aq3z13xmh1aN%liz@poppyrecords.invalid.invalid>:
If the Raspberry Pi could be made to fire itself up without any
AFAIK Raspi has no ADC input.
You will have to connect an ADC to the GPIO.
intervention and accept two analogue inputs, that would work. (...but >someone would have to program it for me, or at least lead me through how
to program it.) The 100Kc/s requirement isn't just fanciful >over-specification; this thing works on the signals that are well
outside the audio band and the 'scope needs to display them clearly, >despite all the audio clutter. The H.F. signals are higher amplitude
than the audio but are in the nature of pulses and occur infrequently.
(The analogue scope has to be Z modulated from rate-of-change to
emphasise the pulses and avoid screen burn, but this wouldn't be a
problem with an LCD display.)
1 channel kit: < 7 US dollars:
https://www.ebay.com/itm/295219906968
I cannot even buy the parts here for that price.
LCD 320x240 enough?
Fast CD4053 or something CMOS switch makes 2 channels?
Trigger channel select from a CD4073 flopflop after each scan?
the possibilitiies are endless
Knowing programming is almost a requirement these days (since theseventies) in electronics.
Jasen Betts <usenet@revmaps.no-ip.org> wrote:
On 2024-08-28, Don Y <blockedofcourse@foo.invalid> wrote:
On 8/28/2024 7:47 AM, Martin Brown wrote:
On 28/08/2024 08:39, Liz Tuddenham wrote:
The recent thread on high-end oscilloscopes has reminded me of a project >>>>> that I shelved some years ago and might be due for resurrection:Â I am >>>>> looking for a real-time display about 3" x 4" that can behave as an X-Y >>>>> oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be >>>>> ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output >>>>> from a stereo gramophone cartridge, which allows me to check historic >>>>> discs for damage or faulty recording geometry. The tube is about 14" >>>>> long, which means it has to be a standalone shelf unit and I can't build >>>>> anything like it into portable equipment.
I think that Daqarta software can probably do about what you want using >>>> the PC stereo soundcard to digitise X & Y. 100kHz bandwidth might be
pushing it but it should be fine for audio up to 20kHz.
or any other sound card scope software,
Does it *simultaneously* sample each channel? Or, toggle between them?
It makes an audio recording using commodity PC sound hardware.
https://www.ti.com/product/PCM2900C has 2 ADC channels
The advantage would be that you could locate the data acquisition
hardware separately from the (COTS) display.
It's starting to feel like raspberry pi + LCD display + usb sound card.
The first bit sounds OK apart from the programming. This is a
standalone piece of analogue equipment, so there is no computer, no USB
and no sound card (nor any possibility of them).
If the Raspberry Pi could be made to fire itself up without any
intervention and accept two analogue inputs, that would work. (...but someone would have to program it for me, or at least lead me through how
to program it.) The 100Kc/s requirement isn't just fanciful over-specification; this thing works on the signals that are well
outside the audio band and the 'scope needs to display them clearly,
despite all the audio clutter. The H.F. signals are higher amplitude
than the audio but are in the nature of pulses and occur infrequently.
(The analogue scope has to be Z modulated from rate-of-change to
emphasise the pulses and avoid screen burn, but this wouldn't be a
problem with an LCD display.)
Jan Panteltje <alien@comet.invalid> wrote:
On a sunny day (Thu, 29 Aug 2024 10:43:29 +0100) it happened
liz@poppyrecords.invalid.invalid (Liz Tuddenham) wrote in
<1qz1rr1.1p7aq3z13xmh1aN%liz@poppyrecords.invalid.invalid>:
If the Raspberry Pi could be made to fire itself up without any
AFAIK Raspi has no ADC input.
You will have to connect an ADC to the GPIO.
intervention and accept two analogue inputs, that would work. (...but
someone would have to program it for me, or at least lead me through how
to program it.) The 100Kc/s requirement isn't just fanciful
over-specification; this thing works on the signals that are well
outside the audio band and the 'scope needs to display them clearly,
despite all the audio clutter. The H.F. signals are higher amplitude
than the audio but are in the nature of pulses and occur infrequently.
(The analogue scope has to be Z modulated from rate-of-change to
emphasise the pulses and avoid screen burn, but this wouldn't be a
problem with an LCD display.)
1 channel kit: < 7 US dollars:
https://www.ebay.com/itm/295219906968
I cannot even buy the parts here for that price.
LCD 320x240 enough?
That would correspond to a screen 1.6" x 1.2" at 200 dpi, which would be
a bit too small. I would regard 3" x 4" to be the optimum size. and 600
x 800 pixels to be the absolute minimum. There is no need for colour.
Fast CD4053 or something CMOS switch makes 2 channels?
Trigger channel select from a CD4073 flopflop after each scan?
the possibilitiies are endless
I'm not trying to display 2 channels on 1. I need an X-Y display so
that I can see the angle of contact of a stereo stylus with the
roughness of the groove wall and the pattern it traces as it plays the >modulation.
Knowing programming is almost a requirement these days (since the >seventies) in electronics.
I have programmed in Z80 machine code, Algol, Basic, Applescript, PHP
and HTML, but have only used the last two recently. I also don't have
any programming tools as all my designs are analogue.
On a sunny day (Thu, 29 Aug 2024 12:58:10 +0100) it happened liz@poppyrecords.invalid.invalid (Liz Tuddenham) wrote in <1qz1y4l.1m29ncv2qvc1sN%liz@poppyrecords.invalid.invalid>:
Jan Panteltje <alien@comet.invalid> wrote:
On a sunny day (Thu, 29 Aug 2024 10:43:29 +0100) it happened
liz@poppyrecords.invalid.invalid (Liz Tuddenham) wrote in
<1qz1rr1.1p7aq3z13xmh1aN%liz@poppyrecords.invalid.invalid>:
If the Raspberry Pi could be made to fire itself up without any
AFAIK Raspi has no ADC input.
You will have to connect an ADC to the GPIO.
intervention and accept two analogue inputs, that would work. (...but
someone would have to program it for me, or at least lead me through how >> >to program it.) The 100Kc/s requirement isn't just fanciful
over-specification; this thing works on the signals that are well
outside the audio band and the 'scope needs to display them clearly,
despite all the audio clutter. The H.F. signals are higher amplitude
than the audio but are in the nature of pulses and occur infrequently.
(The analogue scope has to be Z modulated from rate-of-change to
emphasise the pulses and avoid screen burn, but this wouldn't be a
problem with an LCD display.)
1 channel kit: < 7 US dollars:
https://www.ebay.com/itm/295219906968
I cannot even buy the parts here for that price.
LCD 320x240 enough?
That would correspond to a screen 1.6" x 1.2" at 200 dpi, which would be
a bit too small. I would regard 3" x 4" to be the optimum size. and 600
x 800 pixels to be the absolute minimum. There is no need for colour.
Fast CD4053 or something CMOS switch makes 2 channels?
Trigger channel select from a CD4073 flopflop after each scan?
the possibilitiies are endless
I'm not trying to display 2 channels on 1. I need an X-Y display so
that I can see the angle of contact of a stereo stylus with the
roughness of the groove wall and the pattern it traces as it plays the >modulation.
Interesting
that is basically the channel separation?
Else get a cheap CRT?
https://www.ebay.com/b/oscilloscope-tube/bn_7024937658
Knowing programming is almost a requirement these days (since the >seventies) in electronics.
I have programmed in Z80 machine code, Algol, Basic, Applescript, PHP
and HTML, but have only used the last two recently. I also don't have
any programming tools as all my designs are analogue.
Anyways, there is a lot to play with...
I build my own PIC programmer... and wrote some software for it:
https://panteltje.nl/panteltje/pic/jppp18/index.html
https://panteltje.nl/panteltje/raspberry_pi_noppp/
PIC asm is not that hard...
One builds up libraries over time.
Jan Panteltje <alien@comet.invalid> wrote:
On a sunny day (Thu, 29 Aug 2024 12:58:10 +0100) it happened
liz@poppyrecords.invalid.invalid (Liz Tuddenham) wrote in
<1qz1y4l.1m29ncv2qvc1sN%liz@poppyrecords.invalid.invalid>:
Jan Panteltje <alien@comet.invalid> wrote:
On a sunny day (Thu, 29 Aug 2024 10:43:29 +0100) it happened
liz@poppyrecords.invalid.invalid (Liz Tuddenham) wrote in
<1qz1rr1.1p7aq3z13xmh1aN%liz@poppyrecords.invalid.invalid>:
If the Raspberry Pi could be made to fire itself up without any
AFAIK Raspi has no ADC input.
You will have to connect an ADC to the GPIO.
intervention and accept two analogue inputs, that would work. (...but >> >> >someone would have to program it for me, or at least lead me through how >> >> >to program it.) The 100Kc/s requirement isn't just fanciful
over-specification; this thing works on the signals that are well
outside the audio band and the 'scope needs to display them clearly,
despite all the audio clutter. The H.F. signals are higher amplitude
than the audio but are in the nature of pulses and occur infrequently. >> >> >(The analogue scope has to be Z modulated from rate-of-change to
emphasise the pulses and avoid screen burn, but this wouldn't be a
problem with an LCD display.)
1 channel kit: < 7 US dollars:
https://www.ebay.com/itm/295219906968
I cannot even buy the parts here for that price.
LCD 320x240 enough?
That would correspond to a screen 1.6" x 1.2" at 200 dpi, which would be
a bit too small. I would regard 3" x 4" to be the optimum size. and 600
x 800 pixels to be the absolute minimum. There is no need for colour.
Fast CD4053 or something CMOS switch makes 2 channels?
Trigger channel select from a CD4073 flopflop after each scan?
the possibilitiies are endless
I'm not trying to display 2 channels on 1. I need an X-Y display so
that I can see the angle of contact of a stereo stylus with the
roughness of the groove wall and the pattern it traces as it plays the
modulation.
Interesting
that is basically the channel separation?
Not really, I need to know the instantaneous vector direction of the
stylus movement. On some 'Mono' recordings it can actually be moving in
a circle (the groove modulation is helical).
~~~~~~ Detailed technical information ~~~~~
This is caused by the cutting face of the recording cutter not being at
right angles to the direction of the groove (sometimes done deliberately
to throw the swarf clear), which results in the modulations on the two
groove walls being out of step with each other. When played with an >elliptical stylus tip, the phase difference generates a vertical
component which muddies the mono sound and plays hell with a declicker. >Twisting the cartridge about a vertical axis will displace the contact
points of the stylus on the groove wall and restore the sound quality
The amount of twist needed will depend on the amount and direction of >misaligment of the cutter, the groove wall angle and the size of stylus
used for playback. The pattern on the X-Y 'scope gives me valuable >information about this effect and enables me to optimaise the playback
angles without a lot of trial and error.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
When playing 'shellac' records (which contain a lot of abrasive) the >roughness on one groove wall displaces the stylus at an angle up and
down the slope of the opposite groove wall. On an X-Y display, without
any modulation this looks like a letter 'X' but the angles of the two
arms of the 'X' may not be at 45 degrees.and may be unequal or even
change as the record revolves. I am dealing with material that may have
been badly recorded and will almost certainly have been damaged by poor >storage and massive playback devices (with heavy resonances). The
'scope is there to enable me to identify and correct as many of the
defects as possible.
Else get a cheap CRT?
https://www.ebay.com/b/oscilloscope-tube/bn_7024937658
There seem to be quite a few to choose from - and I have a couple
complete with their chassis in the attic. It looks as though I am going
to be short of space in the equipment I am designing, so perhaps the >oscilloscope will have to go as a separate item anyway.
Knowing programming is almost a requirement these days (since theseventies) in electronics.
I have programmed in Z80 machine code, Algol, Basic, Applescript, PHP
and HTML, but have only used the last two recently. I also don't have
any programming tools as all my designs are analogue.
Anyways, there is a lot to play with...
I build my own PIC programmer... and wrote some software for it:
https://panteltje.nl/panteltje/pic/jppp18/index.html
https://panteltje.nl/panteltje/raspberry_pi_noppp/
PIC asm is not that hard...
One builds up libraries over time.
That's what a friend keeps telling me. He advocates even the simplest
jobs being done with a microprocessor - but then he never seems to
produce anything that works. At least yours appear to be built and
working.
On 2024-08-28, Don Y <blockedofcourse@foo.invalid> wrote:
On 8/28/2024 7:47 AM, Martin Brown wrote:
On 28/08/2024 08:39, Liz Tuddenham wrote:
The recent thread on high-end oscilloscopes has reminded me of a project >>>> that I shelved some years ago and might be due for resurrection: I am >>>> looking for a real-time display about 3" x 4" that can behave as an X-Y >>>> oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be >>>> ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry. The tube is about 14" >>>> long, which means it has to be a standalone shelf unit and I can't build >>>> anything like it into portable equipment.
I think that Daqarta software can probably do about what you want using the PC
stereo soundcard to digitise X & Y. 100kHz bandwidth might be pushing it but it
should be fine for audio up to 20kHz.
or any other sound card scope software,
Does it *simultaneously* sample each channel? Or, toggle between them?
It makes an audio recording using commodity PC sound hardware. https://www.ti.com/product/PCM2900C has 2 ADC channels
The advantage would be that you could locate the data acquisition
hardware separately from the (COTS) display.
It's starting to feel like raspberry pi + LCD display + usb sound card.
On 8/29/2024 1:57 AM, Jasen Betts wrote:
On 2024-08-28, Don Y <blockedofcourse@foo.invalid> wrote:
On 8/28/2024 7:47 AM, Martin Brown wrote:
On 28/08/2024 08:39, Liz Tuddenham wrote:
The recent thread on high-end oscilloscopes has reminded me of a project >>>>> that I shelved some years ago and might be due for resurrection: I am >>>>> looking for a real-time display about 3" x 4" that can behave as an X-Y >>>>> oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be >>>>> ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output >>>>> from a stereo gramophone cartridge, which allows me to check historic >>>>> discs for damage or faulty recording geometry. The tube is about 14" >>>>> long, which means it has to be a standalone shelf unit and I can't build >>>>> anything like it into portable equipment.
I think that Daqarta software can probably do about what you want using the PC
stereo soundcard to digitise X & Y. 100kHz bandwidth might be pushing it but it
should be fine for audio up to 20kHz.
or any other sound card scope software,
I think the OP wants a "real-time" X-Y display. If it is acceptable to
treat this as a two-step process -- acquire data, display -- then
it becomes a lot easier to implement.
Does it *simultaneously* sample each channel? Or, toggle between them?
It makes an audio recording using commodity PC sound hardware.
https://www.ti.com/product/PCM2900C has 2 ADC channels
But, is that true of ALL "sound cards".
The advantage would be that you could locate the data acquisition
hardware separately from the (COTS) display.
It's starting to feel like raspberry pi + LCD display + usb sound card.
The OP seems to want to avoid writing any code. And, to be fair, capturing two 100KHz signals and pushing them onto a display while ERASING any previous display content is a bit of a job, especially if you want to truly mimic
a 'scope in X-Y mode (where the display's persistence allows some portion
of "old" traces to remain visible before fading away (with the LCD, the software would have to perform that function)
(think about how you would decide *what* to erase, given that a particular pixel may have been painted as part of N consecutive cycles -- even if it
is the "oldest" pixel in a time-sorted list)
On 2024-08-29, Don Y <blockedofcourse@foo.invalid> wrote:
On 8/29/2024 1:57 AM, Jasen Betts wrote:
On 2024-08-28, Don Y <blockedofcourse@foo.invalid> wrote:
On 8/28/2024 7:47 AM, Martin Brown wrote:
On 28/08/2024 08:39, Liz Tuddenham wrote:
The recent thread on high-end oscilloscopes has reminded me of a project >>>>>> that I shelved some years ago and might be due for resurrection: I am >>>>>> looking for a real-time display about 3" x 4" that can behave as an X-Y >>>>>> oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be >>>>>> ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output >>>>>> from a stereo gramophone cartridge, which allows me to check historic >>>>>> discs for damage or faulty recording geometry. The tube is about 14" >>>>>> long, which means it has to be a standalone shelf unit and I can't build >>>>>> anything like it into portable equipment.
I think that Daqarta software can probably do about what you want using the PC
stereo soundcard to digitise X & Y. 100kHz bandwidth might be pushing it but it
should be fine for audio up to 20kHz.
or any other sound card scope software,
I think the OP wants a "real-time" X-Y display. If it is acceptable to
treat this as a two-step process -- acquire data, display -- then
it becomes a lot easier to implement.
I think few millisecods latency will go unnoticed,
Does it *simultaneously* sample each channel? Or, toggle between them? >>>It makes an audio recording using commodity PC sound hardware.
https://www.ti.com/product/PCM2900C has 2 ADC channels
But, is that true of ALL "sound cards".
That is not important, avoid unsuitable devices.
The advantage would be that you could locate the data acquisition
hardware separately from the (COTS) display.
It's starting to feel like raspberry pi + LCD display + usb sound card.
The OP seems to want to avoid writing any code. And, to be fair, capturing >> two 100KHz signals and pushing them onto a display while ERASING any previous
display content is a bit of a job, especially if you want to truly mimic
a 'scope in X-Y mode (where the display's persistence allows some portion
of "old" traces to remain visible before fading away (with the LCD, the
software would have to perform that function)
(think about how you would decide *what* to erase, given that a particular >> pixel may have been painted as part of N consecutive cycles -- even if it
is the "oldest" pixel in a time-sorted list)
store a ring buffer of pixel coordinates and a raster size buffer of
pixel birthdays and then the update process becomes O(1)
look up the age(th) pixel in the buffer, if the age in the birthday map
is wrong then it has since been overwrittenm, so do nothing, else dim it a little.
this won't get you anti-aliasing, which is possibly more valuable,
Maybe there's a way to get both subpixel resolution and a fading effect. >perhaps some sort of palette rotation? does it actually need a >microcontroller? perhaps do the whole thing in an FPGA.
On 2024-08-29, Don Y <blockedofcourse@foo.invalid> wrote:
On 8/29/2024 1:57 AM, Jasen Betts wrote:
On 2024-08-28, Don Y <blockedofcourse@foo.invalid> wrote:
On 8/28/2024 7:47 AM, Martin Brown wrote:
On 28/08/2024 08:39, Liz Tuddenham wrote:
The recent thread on high-end oscilloscopes has reminded me of a project >>>>>> that I shelved some years ago and might be due for resurrection: I am >>>>>> looking for a real-time display about 3" x 4" that can behave as an X-Y >>>>>> oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be >>>>>> ideal.
Currently I am using an actual X-Y oscillocsope to monitor the output >>>>>> from a stereo gramophone cartridge, which allows me to check historic >>>>>> discs for damage or faulty recording geometry. The tube is about 14" >>>>>> long, which means it has to be a standalone shelf unit and I can't build >>>>>> anything like it into portable equipment.
I think that Daqarta software can probably do about what you want using the PC
stereo soundcard to digitise X & Y. 100kHz bandwidth might be pushing it but it
should be fine for audio up to 20kHz.
or any other sound card scope software,
I think the OP wants a "real-time" X-Y display. If it is acceptable to
treat this as a two-step process -- acquire data, display -- then
it becomes a lot easier to implement.
I think few millisecods latency will go unnoticed,
Does it *simultaneously* sample each channel? Or, toggle between them? >>>It makes an audio recording using commodity PC sound hardware.
https://www.ti.com/product/PCM2900C has 2 ADC channels
But, is that true of ALL "sound cards".
That is not important, avoid unsuitable devices.
The advantage would be that you could locate the data acquisition
hardware separately from the (COTS) display.
It's starting to feel like raspberry pi + LCD display + usb sound card.
The OP seems to want to avoid writing any code. And, to be fair, capturing >> two 100KHz signals and pushing them onto a display while ERASING any previous
display content is a bit of a job, especially if you want to truly mimic
a 'scope in X-Y mode (where the display's persistence allows some portion
of "old" traces to remain visible before fading away (with the LCD, the
software would have to perform that function)
(think about how you would decide *what* to erase, given that a particular >> pixel may have been painted as part of N consecutive cycles -- even if it
is the "oldest" pixel in a time-sorted list)
store a ring buffer of pixel coordinates and a raster size buffer of
pixel birthdays and then the update process becomes O(1)
look up the age(th) pixel in the buffer, if the age in the birthday map
is wrong then it has since been overwrittenm, so do nothing, else dim it a little.
this won't get you anti-aliasing, which is possibly more valuable,
Maybe there's a way to get both subpixel resolution and a fading effect. perhaps some sort of palette rotation? does it actually need a microcontroller? perhaps do the whole thing in an FPGA.
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