I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution (particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution >(particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to >screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution (particularly at the centre), green, white or blue trace would be acceptable but multi-colour is not necessary. If it is susceptible to screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
Likely you've done this, but maybe look at https://www.thomaselectronics.com/manufacturers/
It appears they mostly repair and sell refurbished units,
but if anybody knows where to find small crt displays they
seem a good place to start.
I take it you've looked into and rejected using a USB oscilloscope
and a computer? The bootup script would be somewhat easier than
programming a microcontroller, but it won't start instantly.
On Sat, 12 Jul 2025 10:54:03 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am >wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution >(particularly at the centre), green, white or blue trace would be >acceptable but multi-colour is not necessary. If it is susceptible to >screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
Amazon has color LCD oscilloscopes starting around $30.
<bp@www.zefox.net> wrote:
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution
(particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to
screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
Likely you've done this, but maybe look at
https://www.thomaselectronics.com/manufacturers/
It appears they mostly repair and sell refurbished units,
but if anybody knows where to find small crt displays they
seem a good place to start.
I do have a few suitable CTRs hidden away but I wondered if there was a modern alternative. A CRT would need a lot of hardware and extra
analogue design; unless I had a source of replacements, I wouldn't want
to commit myself to one type which might later be unobtainable
I take it you've looked into and rejected using a USB oscilloscope
and a computer? The bootup script would be somewhat easier than
programming a microcontroller, but it won't start instantly.
There is no possibilty of including a computer, this is a piece of semi-portable rack-mounting analogue gear with just a few control knobs
on the front panel.
I was hoping there might have been improvements in this field, but
couldn't find any. Surely there must be a market for a cheap OEM
equivalent to a standalone oscilloscope display without all the
unnecessary 'features' ?
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
<bp@www.zefox.net> wrote:
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
I want to incorporate an oscilloscope display in a piece of equipment. >>> I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It >>> must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution
(particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to >>> screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to >>> use it.
Likely you've done this, but maybe look at
https://www.thomaselectronics.com/manufacturers/
It appears they mostly repair and sell refurbished units,
but if anybody knows where to find small crt displays they
seem a good place to start.
I do have a few suitable CTRs hidden away but I wondered if there was a modern alternative. A CRT would need a lot of hardware and extra
analogue design; unless I had a source of replacements, I wouldn't want
to commit myself to one type which might later be unobtainable
I take it you've looked into and rejected using a USB oscilloscope
and a computer? The bootup script would be somewhat easier than
programming a microcontroller, but it won't start instantly.
There is no possibilty of including a computer, this is a piece of semi-portable rack-mounting analogue gear with just a few control knobs
on the front panel.
I was hoping there might have been improvements in this field, but
couldn't find any. Surely there must be a market for a cheap OEM equivalent to a standalone oscilloscope display without all the
unnecessary 'features' ?
DIY steampunk audio is a bit of a niche market. ;)
john larkin <jl@glen--canyon.com> wrote:
On Sat, 12 Jul 2025 10:54:03 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution
(particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to
screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
Amazon has color LCD oscilloscopes starting around $30.
I haven't found one that does X-Y display or that starts automtically at >power-on with no menus or user intervention.
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
<bp@www.zefox.net> wrote:
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
I want to incorporate an oscilloscope display in a piece of equipment. >>>>> I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It >>>>> must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution
(particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to >>>>> screen-burn from a stationary spot, DC-coupled Z-mod will be needed. >>>>>
I do not want to have to learn to program a microprocessor in order to >>>>> use it.
Likely you've done this, but maybe look at
https://www.thomaselectronics.com/manufacturers/
It appears they mostly repair and sell refurbished units,
but if anybody knows where to find small crt displays they
seem a good place to start.
I do have a few suitable CTRs hidden away but I wondered if there was a
modern alternative. A CRT would need a lot of hardware and extra
analogue design; unless I had a source of replacements, I wouldn't want
to commit myself to one type which might later be unobtainable
I take it you've looked into and rejected using a USB oscilloscope
and a computer? The bootup script would be somewhat easier than
programming a microcontroller, but it won't start instantly.
There is no possibilty of including a computer, this is a piece of
semi-portable rack-mounting analogue gear with just a few control knobs
on the front panel.
I was hoping there might have been improvements in this field, but
couldn't find any. Surely there must be a market for a cheap OEM
equivalent to a standalone oscilloscope display without all the
unnecessary 'features' ?
DIY steampunk audio is a bit of a niche market. ;)
This is a professional analogue de-clicker, a portable version of the
setup I have been using in the studio to earn my living for the past 30 years. Because it is portable, I was a bit wary about the fragility of
a CRT, even though it is to be built into a hefty flight case.
The X-Y scope is used to analyse the movement of the stylus in the
record groove, which can reveal all sorts of problems that need
correcting to get the best sound quality. A lot of the analogue
computing adjustment is done 'on-the-fly', so a separate knob for each function is the only way of controlling it rapidly and accurately
enough. Menus and keyboards would be hopeless.
I do have a few suitable CTRs hidden away but I wondered if there was a modern alternative. A CRT would need a lot of hardware and extra
analogue design; unless I had a source of replacements, I wouldn't want
to commit myself to one type which might later be unobtainable
There is no possibilty of including a computer, this is a piece of semi-portable rack-mounting analogue gear with just a few control knobs
on the front panel.
On 7/12/2025 8:59 AM, Liz Tuddenham wrote:
I do have a few suitable CTRs hidden away but I wondered if there was a modern alternative. A CRT would need a lot of hardware and extra
analogue design; unless I had a source of replacements, I wouldn't want
to commit myself to one type which might later be unobtainable
There is no possibilty of including a computer, this is a piece of semi-portable rack-mounting analogue gear with just a few control knobs
on the front panel.
"Including a computer" need not impact the "control knobs on
the front panel" -- any more than the slot machine at the casino
or the gas (petrol) pump at the filling station adds anything
to the UI that isn't demanded by the application itself
(e.g., power).
Think "deeply embedded".
Nowadays, small/cheap computers are so much more capable
(MIPS) that you can likely *script* an application and
never really have to know how to "program a computer".
[My customers -- Grandpa John and Grandma Jane Dough -- are
expected to be able to write simple scripts to customize
the system for their needs. The trick is finding a scripting
language that best expresses the typical goals in a concise
manner without obsessing over syntax.]
Reformulating your question (in a wider group) with this sort
of goal might give you a ready-made solution -- that just requires
you to nail down the edges so the script starts as soon as power
is applied (also a common goal).
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution (particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution (particularly at the centre), green, white or blue trace would be acceptable but multi-colour is not necessary. If it is susceptible to screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
I wonder if you could take a display with a VGA input and craft something to generate VGA signals.
First you need to generate VGA hsync / vsync. That's some digital counters driven off the appropriate crystal with resets at the right number of counts for the VGA mode and some logic gates to drive the syncs for the right
number of cycles. (Look up VGA timings for the details)
Then you could make a comparator based ADC. Feed the X value from your counters into a DAC which feeds a pair of comparators. Put your X signal into the other side of the comparators. Each one is slightly biased so you get a function of (Xinput - bias < counter < Xinput + bias). Do the same with a pair of comparators for the Y side. AND the four outputs together
and scale to VGA signal levels.
This makes the logic:
IF (Xpos > Xinput - bias) AND (Xpos < Xinput + bias)
AND
(Ypos > Yinput - bias) AND (Ypos < Yinput + bias)
THEN
output := VGA_white
ELSE
output := VGA_black
ENDIF
The 'bias' is the size of your dot. If you want a white dot wire this to R/G/B signals, if green only to G, blue only to B, etc.
By changing the clock frequency and counter wraparound values you can target any standard resolution and timings a monitor can handle, up to roughly
1080p which is often the maximum a monitor will handle on the VGA port. You are then free to pick whatever display you like, from tiny to a giant TV or projector. Typically modes would be 60Hz, but a fancy gaming monitor might be able to go higher with a low lag. A CRT monitor would have the lowest lag, and if it breaks you can replace with any other you can source (worst case an LCD).
Theo <theom+news@chiark.greenend.org.uk> wrote:
By changing the clock frequency and counter wraparound values you can target
any standard resolution and timings a monitor can handle, up to roughly 1080p which is often the maximum a monitor will handle on the VGA port. You
are then free to pick whatever display you like, from tiny to a giant TV or projector. Typically modes would be 60Hz, but a fancy gaming monitor might be able to go higher with a low lag. A CRT monitor would have the lowest lag, and if it breaks you can replace with any other you can source (worst case an LCD).
Other thing though - with this approach you'll get one dot per frame (60
to maybe 144Hz). I suppose what you mean by 100KHz input bandwidth is you want some degree of persistence in the display - even if the dot sweep is 100KHz the phosphor will retain it for longer. This is hard to do in logic.
By changing the clock frequency and counter wraparound values you can target any standard resolution and timings a monitor can handle, up to roughly
1080p which is often the maximum a monitor will handle on the VGA port. You are then free to pick whatever display you like, from tiny to a giant TV or projector. Typically modes would be 60Hz, but a fancy gaming monitor might be able to go higher with a low lag. A CRT monitor would have the lowest lag, and if it breaks you can replace with any other you can source (worst case an LCD).
john larkin <jl@glen--canyon.com> wrote:
On Sat, 12 Jul 2025 10:54:03 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution
(particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to
screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
Amazon has color LCD oscilloscopes starting around $30.
I haven't found one that does X-Y display or that starts automtically at >power-on with no menus or user intervention.
john larkin <jl@glen--canyon.com> wrote:
On Sat, 12 Jul 2025 10:54:03 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution
(particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to
screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
Amazon has color LCD oscilloscopes starting around $30.
I haven't found one that does X-Y display or that starts automtically at >power-on with no menus or user intervention.
On Sat, 12 Jul 2025 17:55:17 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sat, 12 Jul 2025 10:54:03 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution
(particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to
screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
Amazon has color LCD oscilloscopes starting around $30.
I haven't found one that does X-Y display or that starts automtically at >power-on with no menus or user intervention.
I think the JYETech Wave2 (with a battery option) would do that, but
the display is small.
Reformulating your question (in a wider group) with this sort
of goal might give you a ready-made solution -- that just requires
you to nail down the edges so the script starts as soon as power
is applied (also a common goal).
I appreciate that this is would be a good solution from your position,
but I haven't had any contact with that sort of hardware at all. To incorporate it in a piece of equipment would require me to spend many
months catching up on developments that I have ignored for the last 25
years.
In less than a week I could make an adequate CRT oscilloscope from
scratch and it would do exactly what I want, apart from having difficult-to-replace parts with limited lifespan. (It would also take
up a lot more space.)
Hmm, an electrostatic-deflection CRT and four EF91s would do the job
with a lot less bother.
Theo <theom+news@chiark.greenend.org.uk> wrote:
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution
(particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to
screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
I wonder if you could take a display with a VGA input and craft something to >> generate VGA signals.
First you need to generate VGA hsync / vsync. That's some digital counters >> driven off the appropriate crystal with resets at the right number of counts >> for the VGA mode and some logic gates to drive the syncs for the right
number of cycles. (Look up VGA timings for the details)
Then you could make a comparator based ADC. Feed the X value from your
counters into a DAC which feeds a pair of comparators. Put your X signal
into the other side of the comparators. Each one is slightly biased so you >> get a function of (Xinput - bias < counter < Xinput + bias). Do the same
with a pair of comparators for the Y side. AND the four outputs together
and scale to VGA signal levels.
This makes the logic:
IF (Xpos > Xinput - bias) AND (Xpos < Xinput + bias)
AND
(Ypos > Yinput - bias) AND (Ypos < Yinput + bias)
THEN
output := VGA_white
ELSE
output := VGA_black
ENDIF
The 'bias' is the size of your dot. If you want a white dot wire this to
R/G/B signals, if green only to G, blue only to B, etc.
By changing the clock frequency and counter wraparound values you can target >> any standard resolution and timings a monitor can handle, up to roughly
1080p which is often the maximum a monitor will handle on the VGA port. You >> are then free to pick whatever display you like, from tiny to a giant TV or >> projector. Typically modes would be 60Hz, but a fancy gaming monitor might >> be able to go higher with a low lag. A CRT monitor would have the lowest
lag, and if it breaks you can replace with any other you can source (worst >> case an LCD).
Hmm, an electrostatic-deflection CRT and four EF91s would do the job
with a lot less bother.
Amazon has color LCD oscilloscopes starting around $30.
I haven't found one that does X-Y display or that starts automtically at
power-on with no menus or user intervention.
I think the JYETech Wave2 (with a battery option) would do that, but
the display is small.
That would be just right - if only the screen was much bigger. I really
need to be able to see detail equivalent to one pixel on that screen -
so perhaps it might work with a x2 magnifier that brought it up to the >equivalent of 5" diagonal.
I've had a look at the operating manual and the "X-Y" mode shows a
sampling rate of 5 kHz in a highlighted panel, as if that is fixed in
that mode. I need at least 100 kHz sampling in each channel, otherwise
it may miss details.
On Sun, 13 Jul 2025 17:33:48 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
<snip>
Amazon has color LCD oscilloscopes starting around $30.
I haven't found one that does X-Y display or that starts automtically at >> >power-on with no menus or user intervention.
I think the JYETech Wave2 (with a battery option) would do that, but
the display is small.
That would be just right - if only the screen was much bigger. I really >need to be able to see detail equivalent to one pixel on that screen -
so perhaps it might work with a x2 magnifier that brought it up to the >equivalent of 5" diagonal.
I've had a look at the operating manual and the "X-Y" mode shows a
sampling rate of 5 kHz in a highlighted panel, as if that is fixed in
that mode. I need at least 100 kHz sampling in each channel, otherwise
it may miss details.
Although a digital scope may record information that occurred at high frequency, it isn.t going to refresh it's display any faster than the
eye can perceive it.
Reformulating your question (in a wider group) with this sort
of goal might give you a ready-made solution -- that just requires
you to nail down the edges so the script starts as soon as power
is applied (also a common goal).
I appreciate that this is would be a good solution from your position,
but I haven't had any contact with that sort of hardware at all. To incorporate it in a piece of equipment would require me to spend many months catching up on developments that I have ignored for the last 25 years.
A dangerous practice in engineering.
In less than a week I could make an adequate CRT oscilloscope from
scratch and it would do exactly what I want, apart from having difficult-to-replace parts with limited lifespan. (It would also take
up a lot more space.)
And, be constrained to behave only as it has in a previous life.
Instead, see the opportunity as a chance to add new value. E.g.,
I developed scene analysis software to recognize persons in and
around the house. Once I had that tool in my arsenal, I found
lots of other applications.
You might, for example, create a nonlinear display to emphasize
behaviour in certain portions of the display
-- perhaps even highlighting
it (color) *or* automatically *capturing* it. Replaying captured data so you could "single step" the display in search of artifacts.
Or, allowing you (customer) to view the display on their phone
instead of having to be "with" the equipment.
On Sun, 13 Jul 2025 16:36:58 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
Theo <theom+news@chiark.greenend.org.uk> wrote:
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
I want to incorporate an oscilloscope display in a piece of equipment. >> > I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It >> > must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution
(particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to >> > screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to >> > use it.
I wonder if you could take a display with a VGA input and craft
something to generate VGA signals.
First you need to generate VGA hsync / vsync. That's some digital
counters driven off the appropriate crystal with resets at the right
number of counts for the VGA mode and some logic gates to drive the
syncs for the right number of cycles. (Look up VGA timings for the
details)
Then you could make a comparator based ADC. Feed the X value from your
counters into a DAC which feeds a pair of comparators. Put your X
signal into the other side of the comparators. Each one is slightly
biased so you get a function of (Xinput - bias < counter < Xinput +
bias). Do the same with a pair of comparators for the Y side. AND the
four outputs together and scale to VGA signal levels.
This makes the logic:
IF (Xpos > Xinput - bias) AND (Xpos < Xinput + bias)
AND
(Ypos > Yinput - bias) AND (Ypos < Yinput + bias)
THEN
output := VGA_white
ELSE
output := VGA_black
ENDIF
The 'bias' is the size of your dot. If you want a white dot wire this to >> R/G/B signals, if green only to G, blue only to B, etc.
By changing the clock frequency and counter wraparound values you can
target any standard resolution and timings a monitor can handle, up to
roughly 1080p which is often the maximum a monitor will handle on the
VGA port. You are then free to pick whatever display you like, from
tiny to a giant TV or projector. Typically modes would be 60Hz, but a
fancy gaming monitor might be able to go higher with a low lag. A CRT
monitor would have the lowest lag, and if it breaks you can replace
with any other you can source (worst case an LCD).
Hmm, an electrostatic-deflection CRT and four EF91s would do the job
with a lot less bother.
Needs a - HV supply for the CRT, +HV for the tubes, separate filament supplies, maybe a magnetic shield.
And lots of packaging/plumbing.
An LCD implementation would be small and simple and cost $20-50. And
have nice colors.
And be more reliable.
I appreciate that this is would be a good solution from your position,
but I haven't had any contact with that sort of hardware at all. To
incorporate it in a piece of equipment would require me to spend many
months catching up on developments that I have ignored for the last 25
years.
A dangerous practice in engineering.
I have had to concentrate on things that made my particular niche market
better. Many years ago I programmed a Z80 but that was for a particular
task that was best done that way. Whilst things like the Raspberry Pie
might be almost good enough for occasional specific needs (or they might not), the effort involved in learning to use them and buying all the peripherals to program them have never been worthwhile.
In less than a week I could make an adequate CRT oscilloscope from
scratch and it would do exactly what I want, apart from having
difficult-to-replace parts with limited lifespan. (It would also take
up a lot more space.)
And, be constrained to behave only as it has in a previous life.
Exactly. The one I modified in the 1980s has been doing the job ever
since (with only one tube change) and shows no signs of any
shortcomings. It doesn't need to do anything else and if it did, I
couldn't use it for that without disconnecting the whole set-up. All I
want is a portable version of the same thing, dedicated to a single
task.
You might, for example, create a nonlinear display to emphasize
behaviour in certain portions of the display
I tried that on another version using the V/I characteristics of diodes,
it gave an unrealistic view of what was happening and made analysis unreliable.
-- perhaps even highlighting
it (color) *or* automatically *capturing* it. Replaying captured data so you
could "single step" the display in search of artifacts.
The highlighting is done with the Z-mod, which brightens-up the trace
when the dV/dt of the X or Y exceeds a certain value. I need to be able
to see what is happening in real time so that I can adjust the controls
on the analogue computer. I have taken screen photographs (with a
digital camera) to illustrate certain aspects of the process, but these
were no help to me whilst doing the job.
Or, allowing you (customer) to view the display on their phone
instead of having to be "with" the equipment.
Sorry, no help whatsoever. This is to be used in conjunction with
portable record playing equipment and an analogue computer for
de-crackling old records in real time whilst listening to the sound on
high quality monitor loudspeakers. The 'demand' (such as there is) is
for getting the results; nobody has shown more than a passing interest
in how I do it and I have only sold one set of equipment in 30 years.
The portable equipment, as far as it is built, is shown at: <http://www.poppyrecords.co.uk/other/Turntables/parallel-tracker.htm>
There are spare panels on the left which could house the extra analogue controls and a flat-panel X-Y scope. The analogue computer boards (nine
of them) would just fit into the right hand side underneath the
turntable and, with a good loudspeaker built into the removeable lid,
the whole unit would be self-contained. That was the original plan.
The loudspeaker idea has already fallen by the wayside because there
isn't enough depth in the lid for the large magnet of something like a
KEF B110 and the bass respose on a panel that size would be inadequate.
A deeper lid would make the whole thing unmanageable - it is already
quite hernia-inducing to lift.
If I have to use an oscilloscope tube, I would have to build that into a separate unit; the computer could then be rack-mounted alongside the
display. Something like a 19" rack flight case, about the same size as
the turntable unit, would then be needed. The cards could slide into a frame, each with its own front panel, and the oscilloscope could be
built between a pair of metal 'cards' that slid in alongside the others.
The equipment then becomes three units: the turntable, the computer and
the loudspeaker. If the cables and accessories can't be fitted into the
lid of the turntable and the flight case, a fourth box then become
necessary. It is now a long way from the compact single unit I
envisiaged at the start of the project.
I thought I would ask again here and have one last try at obtaining a suitable X-Y display before I abandoned the 'compact' version and
started down the oscilloscope-in-a-separate-rack road. The whole thing
has to be working reliable ready for use in public on the first week in October.
On 7/15/2025 2:33 AM, Liz Tuddenham wrote:
I appreciate that this is would be a good solution from your position, >>> but I haven't had any contact with that sort of hardware at all. To
incorporate it in a piece of equipment would require me to spend many
months catching up on developments that I have ignored for the last 25 >>> years.
A dangerous practice in engineering.
I have had to concentrate on things that made my particular niche market
Sure, but markets tend to disappear and/or morph in ways that can't
be foreseen. IME, it pays to always keep exploring the edges for
new opportunities. This usually requires new skillsets.
better. Many years ago I programmed a Z80 but that was for a particular task that was best done that way. Whilst things like the Raspberry Pie might be almost good enough for occasional specific needs (or they might not), the effort involved in learning to use them and buying all the peripherals to program them have never been worthwhile.
That's not a big cost, nowadays. I recall paying $15K for a Unisite,
$25K for (each of several) ICEs, etc.
A firm I was with made process control equipment for Pharma. The
Old Timer couldn't understand why we needed to come up with a NEW *computerized* version of the ANALOG control system that had been
in use to that point. (the "control" handled by switches that
were engaged when the needle of the indicator deviated from it's
nominal set point -- in BogoUnits)
"This still works!"
"Yes, it does. Exactly as it did many years ago when it was
designed. It does exactly AND ONLY that."
Are you sure there aren't other capabilities that you *could*
provide, if designing from scratch, TODAY -- esp based on your
past experiences?
You might, for example, create a nonlinear display to emphasize
behaviour in certain portions of the display
I tried that on another version using the V/I characteristics of diodes,
it gave an unrealistic view of what was happening and made analysis unreliable.
But you could codify the analysis into the instrument. Have *it*
sort out what is happening and just alert you to its observations.
You keep no records of each "job"?
My point was that once
digitalized, you can distribute/store the imagery however you want.
[...]The portable equipment, as far as it is built, is shown at: <http://www.poppyrecords.co.uk/other/Turntables/parallel-tracker.htm>
I thought I would ask again here and have one last try at obtaining a suitable X-Y display before I abandoned the 'compact' version and
started down the oscilloscope-in-a-separate-rack road. The whole thing
has to be working reliable ready for use in public on the first week in October.
Then I guess you will have to accept limited spares availability and increased product size.
Good luck!
legg <legg@nospam.magma.ca> wrote:
On Sun, 13 Jul 2025 17:33:48 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
<snip>
Amazon has color LCD oscilloscopes starting around $30.
I haven't found one that does X-Y display or that starts automtically at >> >> >power-on with no menus or user intervention.
I think the JYETech Wave2 (with a battery option) would do that, but
the display is small.
That would be just right - if only the screen was much bigger. I really
need to be able to see detail equivalent to one pixel on that screen -
so perhaps it might work with a x2 magnifier that brought it up to the
equivalent of 5" diagonal.
I've had a look at the operating manual and the "X-Y" mode shows a
sampling rate of 5 kHz in a highlighted panel, as if that is fixed in
that mode. I need at least 100 kHz sampling in each channel, otherwise
it may miss details.
Although a digital scope may record information that occurred at high
frequency, it isn.t going to refresh it's display any faster than the
eye can perceive it.
If it can't refresh the display at the same speed as the data capture
(albeit with a slight lag), it will have to either concatenate several
data points into one display frame or omit some of the data. I doubt if
any of the cheaper displays would include information about that in the >specification.
I am looking at the vectorial stylus movement of a stereo gramophone
pickup. Rough particles generate infrequent transients at various
angles, depending on the contact angle between the stylus and the groove >wall. These crackle patterns also show whether the stylus fits the
groove properly and which size of stylus fits best.
Certain types of recording artifacts produce looping patterns which
depend on the frequency being recorded, they tell the transcription
engineer which type of recording equipment was in use at the time and
can be a great help in setting up the correct replay characteristics.
The distortion they generate can be minimised by altering the playback >geometry.
Damaged groove walls generate other characteristic patterns and the
balance between the right and left channels may have to be skewed to
minimise the unwanted noise and distortion
Because of this, it is critical to be able to judge the angle and shape
of these random excursions so that the proper correction can be applied.
A modified X-Y oscilloscope has proved to be the best tool for the job
since the 1980s but I was hoping that there might now be something >off-the-shelf that would be a drop-in replacement.
It looks as though the trend for digital 'extras' has compromised the
basic functions, at least in the cheaper equipment but I might buy one
and see if it will do the job in spite of the shortcomings.
better. Many years ago I programmed a Z80 but that was for a particular >>> task that was best done that way. Whilst things like the Raspberry Pie
might be almost good enough for occasional specific needs (or they might >>> not), the effort involved in learning to use them and buying all the
peripherals to program them have never been worthwhile.
That's not a big cost, nowadays. I recall paying $15K for a Unisite,
$25K for (each of several) ICEs, etc.
Those prices are completely beyond anything I could afford. All my
equipment put together hasn't cost that much.
[...]
A firm I was with made process control equipment for Pharma. The
Old Timer couldn't understand why we needed to come up with a NEW
*computerized* version of the ANALOG control system that had been
in use to that point. (the "control" handled by switches that
were engaged when the needle of the indicator deviated from it's
nominal set point -- in BogoUnits)
"This still works!"
"Yes, it does. Exactly as it did many years ago when it was
designed. It does exactly AND ONLY that."
...and it only needed to do that, so what was the problem that needed to
be solved?
Are you sure there aren't other capabilities that you *could*
provide, if designing from scratch, TODAY -- esp based on your
past experiences?
None that I have identified (other than those I have already dealt with
by small modifications). Nobody else has come up with any equipment
that is even as good as this for this particular job and the only reason
I am building new equipment is to be able to carry it around for
occasional demonstrations.
I have suggested modifications to other people's equipment based on my experience but they have always 'known better', because they were more focussed on selling it than on getting it right.
You might, for example, create a nonlinear display to emphasize
behaviour in certain portions of the display
I tried that on another version using the V/I characteristics of diodes, >>> it gave an unrealistic view of what was happening and made analysis
unreliable.
But you could codify the analysis into the instrument. Have *it*
sort out what is happening and just alert you to its observations.
It simply needs to display the vectors correctly so that I can try to
work out what they mean.
Every pressing of every record is different
and the display is a combination of many factors, there is no way
software could sort that out.
i sometimes have to sit for hours trying
to work out the conditions under which that particular record was made
and how it affected the decisions made by the recording engineer - and
then how to get the best out of the surviving results.
My point was that once
digitalized, you can distribute/store the imagery however you want.
The customers wouldn't have a clue what I was showing them, they only
care about the final version. Very rarely I record the two channels
direct from the pickup pre-eamplifiers but the limited bandwidth of the recording system means that that recording doesn't contain all the information. Also, if the vectors show that I have got something mechanically wrong, it need to be put right on the spot before the
source material has been returned to its owner.
[...]The portable equipment, as far as it is built, is shown at:
<http://www.poppyrecords.co.uk/other/Turntables/parallel-tracker.htm>
I thought I would ask again here and have one last try at obtaining a
suitable X-Y display before I abandoned the 'compact' version and
started down the oscilloscope-in-a-separate-rack road. The whole thing
has to be working reliable ready for use in public on the first week in
October.
Then I guess you will have to accept limited spares availability and
increased product size.
I have bitten the bullet and tried to order a Mini Oscilloscope kit but
the supplier's purchasing website won't accept a UK landline telephone number. I tried to order one from a Dutch supplier but they will only deliver to addresses in continental Europe.
better. Many years ago I programmed a Z80 but that was for a particular >>>> task that was best done that way. Whilst things like the Raspberry Pie >>>> might be almost good enough for occasional specific needs (or they might >>>> not), the effort involved in learning to use them and buying all the
peripherals to program them have never been worthwhile.
That's not a big cost, nowadays. I recall paying $15K for a Unisite,
$25K for (each of several) ICEs, etc.
Those prices are completely beyond anything I could afford. All my
equipment put together hasn't cost that much.
I spent about $25-30K each year on equipment. I learned from prior
9-5 employers the cost of "saving money" on tools so would always
opt to put money into a tool instead of (wasting) my time without it.
After all, the customer ends up paying for it, in the end (either
in my taking longer to accomplish something *or* investing in a
reusable tool).
It is only recently that I have stopped spending money on hardware
as there is just *so* much of it available "for a song" that buying
new is foolhardy (unless you truly need state of the art and, IMO,
most people just THINK they do)
[...]
A firm I was with made process control equipment for Pharma. The
Old Timer couldn't understand why we needed to come up with a NEW
*computerized* version of the ANALOG control system that had been
in use to that point. (the "control" handled by switches that
were engaged when the needle of the indicator deviated from it's
nominal set point -- in BogoUnits)
"This still works!"
"Yes, it does. Exactly as it did many years ago when it was
designed. It does exactly AND ONLY that."
...and it only needed to do that, so what was the problem that needed to
be solved?
It didn't provide an audit trail ("where was the needle at all times
during the 8 hour run?"), didn't handle individual variation well
(if you're producing 200 items per second, how responsive do you think
an analog meter will be IF IT IS THE DECISION VARIABLE?), it didn't
reflect cGMP (if the rest of the industry is moving in an accepted
direction and you aren't, then you can't claim to be providing the same >standard of manufacturing that they are), it operated in bogounits
(percent of full scale deviation -- what's "full scale" mean??), it
was entirely manual in calibration and setup, etc.
But, it was something the Old Timer could wrap his head around.
Anything computerized was threatening. He couldn't understand how
it worked or how it cold "break".
He similarly embraced the use of "significance" in part numbering
as he had convinced himself that he could decode any part number in his
head (and, deluded himself into thinking that was a valuable skill!):
"What's the part number for the *programmed* third EPROM in the XYZ
product?" "Um, I'll have to look that up!" "Will it bear any relationship >to the part number for the 4th EPROM? Or, the 3rd EPROM in the ABC
product?"
Are you sure there aren't other capabilities that you *could*
provide, if designing from scratch, TODAY -- esp based on your
past experiences?
None that I have identified (other than those I have already dealt with
by small modifications). Nobody else has come up with any equipment
that is even as good as this for this particular job and the only reason
I am building new equipment is to be able to carry it around for
occasional demonstrations.
So, you're building a *tool* for yourself -- not a product to sell?
I have suggested modifications to other people's equipment based on my
experience but they have always 'known better', because they were more
focussed on selling it than on getting it right.
I used to call this the Flintstone Syndrome: folks created their
first stone-age vehicles with square-ish tires (made of stone).
Over time, the high spots would wear off, rounding the tire out.
At which time, they would REPLACE the tires as they were clearly
"worn out"!
You might, for example, create a nonlinear display to emphasize
behaviour in certain portions of the display
I tried that on another version using the V/I characteristics of diodes, >>>> it gave an unrealistic view of what was happening and made analysis
unreliable.
But you could codify the analysis into the instrument. Have *it*
sort out what is happening and just alert you to its observations.
It simply needs to display the vectors correctly so that I can try to
work out what they mean.
So, *you* are part of the instrument. I.e., it's NOT a product but,
rather, a data collection/presentation aid.
Every pressing of every record is different
and the display is a combination of many factors, there is no way
software could sort that out.
You would truly be surprised at what software can do -- you just
need to train it. There are limits to the physics involved in >pressing/cutting a piece of vinyl as well as limits on the vinyl
that was actually pressed. (e.g., there can't be a 3 inch warp
in the vinyl).
An advantage it has is that it can laboriously check things that
would otherwise be tedious to do, manually. Or, *remember* as
possibilities -- esp if only rarely encountered.
Domain specific knowledge.
E.g., you can tell if air has become entrapped in the granulation
("powder") being used to form THIS particular tablet (out of the
million you will produce this hour) by examining the pressure
as it is being compressed. So, you will KNOW that the tablet will
be defective a fraction of a second from now when that entrapped
air "pops" the top off the tablet when the pressure is removed.
Otherwise, you'll need to visually inspect them (at 200Hz) in
the hope of catching it!
[I always chuckle when I see people visually inspecting products on
a moving assembly line/conveyor. How "reliable" is that??]
i sometimes have to sit for hours trying
to work out the conditions under which that particular record was made
and how it affected the decisions made by the recording engineer - and
then how to get the best out of the surviving results.
My point was that once
digitalized, you can distribute/store the imagery however you want.
The customers wouldn't have a clue what I was showing them, they only
care about the final version. Very rarely I record the two channels
direct from the pickup pre-eamplifiers but the limited bandwidth of the
recording system means that that recording doesn't contain all the
information. Also, if the vectors show that I have got something
mechanically wrong, it need to be put right on the spot before the
source material has been returned to its owner.
So, you start with a piece of vinyl? And, end up with...?
[...]The portable equipment, as far as it is built, is shown at:
<http://www.poppyrecords.co.uk/other/Turntables/parallel-tracker.htm>
I thought I would ask again here and have one last try at obtaining a
suitable X-Y display before I abandoned the 'compact' version and
started down the oscilloscope-in-a-separate-rack road. The whole thing >>>> has to be working reliable ready for use in public on the first week in >>>> October.
Then I guess you will have to accept limited spares availability and
increased product size.
I have bitten the bullet and tried to order a Mini Oscilloscope kit but
the supplier's purchasing website won't accept a UK landline telephone
number. I tried to order one from a Dutch supplier but they will only
deliver to addresses in continental Europe.
Too funny. "What other things can we do to minimize the number of sales >we'll make?"
I am building new equipment is to be able to carry it around for
occasional demonstrations.
So, you're building a *tool* for yourself -- not a product to sell?
I have suggested modifications to other people's equipment based on my experience but they have always 'known better', because they were more focussed on selling it than on getting it right.
I used to call this the Flintstone Syndrome: folks created their
first stone-age vehicles with square-ish tires (made of stone).
Over time, the high spots would wear off, rounding the tire out.
At which time, they would REPLACE the tires as they were clearly
"worn out"!
It simply needs to display the vectors correctly so that I can try to
work out what they mean.
So, *you* are part of the instrument. I.e., it's NOT a product but,
rather, a data collection/presentation aid.
Every pressing of every record is different
and the display is a combination of many factors, there is no way
software could sort that out.
You would truly be surprised at what software can do -- you just
need to train it.
An advantage it has is that it can laboriously check things that
would otherwise be tedious to do, manually. Or, *remember* as
possibilities -- esp if only rarely encountered.
So, you start with a piece of vinyl? And, end up with...?
I have bitten the bullet and tried to order a Mini Oscilloscope kit but
the supplier's purchasing website won't accept a UK landline telephone number. I tried to order one from a Dutch supplier but they will only deliver to addresses in continental Europe.
Too funny. "What other things can we do to minimize the number of sales we'll make?"
You seem to be looking for sound recovery, rather than cutting
masters.
There's probably a program or app for that.
I am building new equipment is to be able to carry it around for
occasional demonstrations.
So, you're building a *tool* for yourself -- not a product to sell?
Yes, the 'product' is what the tool can do (a 'service' I provide). In
the case of the portable kit, it is mainly intended for demonstation
purposes but could be taken to the cuatomer if the recordings are too valuable to be allowed off the customer's premises.
I have suggested modifications to other people's equipment based on my
experience but they have always 'known better', because they were more
focussed on selling it than on getting it right.
I used to call this the Flintstone Syndrome: folks created their
first stone-age vehicles with square-ish tires (made of stone).
Over time, the high spots would wear off, rounding the tire out.
At which time, they would REPLACE the tires as they were clearly
"worn out"!
I'm not sure if that applies here - but it is an amusing concept.
[The story is that Microsoft re-invented the wheel but they made it
square. Next year's model will be a big improvement because it will be triangular, so it only gives three bumps per revolution.]
It simply needs to display the vectors correctly so that I can try to
work out what they mean.
So, *you* are part of the instrument. I.e., it's NOT a product but,
rather, a data collection/presentation aid.
Yes, it tells me if the analogue computer settings are well-matched to
the signals coming off the record. From that I can work out which of
many parameters need changing and which way to change them on-the-fly (...sometimes with the customer breathing down my neck).
Every pressing of every record is different
and the display is a combination of many factors, there is no way
software could sort that out.
You would truly be surprised at what software can do -- you just
need to train it.
There are things that software can do (mostly related to the time
domain) but it cannot correct faulty playback geometry. At every step
in the recording and palyback chain, errors are introduced; they have to
be undone in the reverse order from that in which they occurred. It is
no use throwing a grossly distorted waveform at software and expecting
it to work out what it looked like before it was subjected to:
Frequency response distortion by the microphone.
Frequency response alteration by pre-emphasis.
Frequency response distortion by the cutterhead.
Groove wall phase errors by a skewed cutter.
Recording machinery noise.
Pressing errors.
Groove damage.
Poor disc material.
Incorrect replay stylus radius.
Tracing distortion on playback.
Azimuth errors on playback.
Speed errors.
Playback machinery noise.
Replay characteristic errors.
...and in what order they occurred.
An advantage it has is that it can laboriously check things that
would otherwise be tedious to do, manually. Or, *remember* as
possibilities -- esp if only rarely encountered.
Most of the errors that require vector analysis are either unique or
occur very infrequently indeed. (The software would have been replaced before the same error occured for a second time.)
So, you start with a piece of vinyl? And, end up with...?
Start with a piece of shellac-slate compound, laminated shellac, nitrate
on glass, nitrate on aluminium, gelatine on glass, gelatine on
cardboard, cellophane on cardboard, embossed solid aluminium,
chalk-filled vinyl (horribly noisy) - and, very rarely, vinyl itself.
The output is a computer file in AIFF which I record to a CDR for the customer. Increasingly, customers are asking for the files on a USB
memory stick in various formats, presumably so they can erase them by accident and expect me to provide another copy a few months later.
I have bitten the bullet and tried to order a Mini Oscilloscope kit but
the supplier's purchasing website won't accept a UK landline telephone
number. I tried to order one from a Dutch supplier but they will only
deliver to addresses in continental Europe.
Too funny. "What other things can we do to minimize the number of sales
we'll make?"
I have also filled in the contact form explaining the telephone number problem to the suppliers, they haven't replied yet.
I am building new equipment is to be able to carry it around for
occasional demonstrations.
So, you're building a *tool* for yourself -- not a product to sell?
Yes, the 'product' is what the tool can do (a 'service' I provide). In
the case of the portable kit, it is mainly intended for demonstation purposes but could be taken to the cuatomer if the recordings are too valuable to be allowed off the customer's premises.
Then you don't really care about replacement parts, costs, etc. I.e.,
you could buy enough "spares" to keep "it" operational until you plan
on exiting the industry.
So, why not guesstimate the likely failure rate in the anticipated
work interval. Double that -- and maybe double it again. Buy that
many spares of the "essential components" and be done with it?
There are things that software can do (mostly related to the time
domain) but it cannot correct faulty playback geometry. At every step
in the recording and palyback chain, errors are introduced; they have to
be undone in the reverse order from that in which they occurred. It is
no use throwing a grossly distorted waveform at software and expecting
it to work out what it looked like before it was subjected to:
Frequency response distortion by the microphone.
Frequency response alteration by pre-emphasis.
Frequency response distortion by the cutterhead.
Groove wall phase errors by a skewed cutter.
Recording machinery noise.
Pressing errors.
Groove damage.
Poor disc material.
Incorrect replay stylus radius.
Tracing distortion on playback.
Azimuth errors on playback.
Speed errors.
Playback machinery noise.
Replay characteristic errors.
...and in what order they occurred.
But, YOU are able to do this. It's not magic. You may not be able to
(at this point in time) identify how you make those decisions. But, there are some criteria that you are using to guide your "adjustments".
A machine can use those same criteria and make those adjustments --- maybe even multiple POSSIBLE approaches to the solution -- reliably and automatically.
I have a knack (some say satanic!) to be able to walk up to a product that I've never seen and find a flaw in its implementation in short order. It
has become a sort of game with my colleagues; at each offsite, they will bring devices that are ready for release to see *if* I can find a flaw
in their implementation.
It's never *if* but, rather, how QUICKLY the flaw will be exposed.
But, I know how I do this -- I just question assumptions. Despite knowing this, they can't seem to question their own assumptions as easily as I can. So, I always "win" the game.
I suspect if you made it a goal to understand your actions, you could similarly "teach" someone/thing to perform comparably.
Most of the errors that require vector analysis are either unique or
occur very infrequently indeed. (The software would have been replaced before the same error occured for a second time.)
But something caused YOU to recognize the error. You would codify those criteria.
So, you start with a piece of vinyl? And, end up with...?
Start with a piece of shellac-slate compound, laminated shellac, nitrate
on glass, nitrate on aluminium, gelatine on glass, gelatine on
cardboard, cellophane on cardboard, embossed solid aluminium,
chalk-filled vinyl (horribly noisy) - and, very rarely, vinyl itself.
The output is a computer file in AIFF which I record to a CDR for the customer. Increasingly, customers are asking for the files on a USB
memory stick in various formats, presumably so they can erase them by accident and expect me to provide another copy a few months later.
Well, you could claim that you don't keep copies of their COPYRIGHTED materials...
So, why not guesstimate the likely failure rate in the anticipated
work interval. Double that -- and maybe double it again. Buy that
many spares of the "essential components" and be done with it?
That is what I have done with my Mac G3s that run my business - but
buying oscilloscope tubes in quantity doesn't seem to be possible
nowadays. I can pick up a few on the secondhand market, but they are
all different.
There are things that software can do (mostly related to the time
domain) but it cannot correct faulty playback geometry. At every step
in the recording and palyback chain, errors are introduced; they have to >>> be undone in the reverse order from that in which they occurred. It is
no use throwing a grossly distorted waveform at software and expecting
it to work out what it looked like before it was subjected to:
Frequency response distortion by the microphone.
Frequency response alteration by pre-emphasis.
Frequency response distortion by the cutterhead.
Groove wall phase errors by a skewed cutter.
Recording machinery noise.
Pressing errors.
Groove damage.
Poor disc material.
Incorrect replay stylus radius.
Tracing distortion on playback.
Azimuth errors on playback.
Speed errors.
Playback machinery noise.
Replay characteristic errors.
...and in what order they occurred.
But, YOU are able to do this. It's not magic. You may not be able to
(at this point in time) identify how you make those decisions. But, there >> are some criteria that you are using to guide your "adjustments".
A machine can use those same criteria and make those adjustments --- maybe >> even multiple POSSIBLE approaches to the solution -- reliably and
automatically.
It has taken me since my childhood to identify these faults and I am
still learning. I have made disc recordings myself, so I know what was involved at the various recording dates of the discs that people bring
me. it would take another lifetime to put all this down in any form,
let alone one compatible with a computer program, and it still wouldn't
be complete because new discoveries are still being made.
I can't imagine a computer 'listening' to a recording and saying "that
noise was the recording engineer engaging the scrolling mechanism prior
to cutting the runout groove". It took several transcription engineers listening to dozens of records over and over, then searching the
archives for evidence of how that particular recording lathe had been
adapted to produce scrolls when automatic stop mechanisms first became available on clockwork gramophones.
Another example: The X-Y display showed strange looping behaviour which varied according to stylus size - but only on certain recordings made
between certain dates on one particular type of cutterhead. This was
traced to the contact points of the rounded stylus in the 'V' groove
(which was unique to this particular manufacturer at the time)
encountering a phase difference between the two groove walls (a bit like azimuth error on a tape head). The larger the stylus, the higher it
rode in the groove and the greater the phase error.
We traced the cause to the Blumlein cutterhead which had the cutter tip trailing on a bar mounted on a vertical-axis pivot with rather low
restoring force. If the cutting facet was not exactly at right angles
to the groove, there was a sideways thrust which drove the stylus bar
further sideways and exacerbated the angular error because of the low restoring force. The cutting lines on two groove walls were displaced
from their correct positions, so the two lots of modulation were out of
phase with each other by an amount that depended on frequency and their height up the groove wall.
Also the suction used for swarf removal could not be very fierce,
otherwise the draught of air past the not-very-stiff cutter produced a
faint roaring background to the recordings - so the engineer always set
the cutting facet at a slight angle to help throw the swarf sideways.
The problem wasn't just caused by an isolated error, it was unwittingly imposed on every recording for reasons that made sense at the time.
This might seem trivial but when the record company started producing frequency test records, they used this cutterhead because it had the
widest response. On the 8 Kc/s band, the phase error was nearly 45
degrees so all the calibration and research subsequently carried out
using this 'definitive' recording was invalid. That discovery was the
result of over 10 years of research.
There are hundreds of examples like this, each one unique.
I have a knack (some say satanic!) to be able to walk up to a product that >> I've never seen and find a flaw in its implementation in short order. It
has become a sort of game with my colleagues; at each offsite, they will
bring devices that are ready for release to see *if* I can find a flaw
in their implementation.
It's never *if* but, rather, how QUICKLY the flaw will be exposed.
...and by whom? The customer?
But, I know how I do this -- I just question assumptions. Despite knowing >> this, they can't seem to question their own assumptions as easily as I can. >> So, I always "win" the game.
I suspect if you made it a goal to understand your actions, you could
similarly "teach" someone/thing to perform comparably.
I have tried to teach several people over the years but they soon loose interest. Many of them don't have enough basic knowledge of physics/ electronics/ engineering to understand the problems and, as long as they
can do a quick-fix based on hearsay, they don't want to learn. Nowadays
most people believe that digital can fix everything.
Most of the errors that require vector analysis are either unique or
occur very infrequently indeed. (The software would have been replaced
before the same error occured for a second time.)
But something caused YOU to recognize the error. You would codify those
criteria.
It isn't just me on my own. I have bookshelves full of books and
documents ranging from research treatise on vibrational analysis through chemistry. electronics and acoustics to reminisences of the early
recording engineers and their personal papers. The computer is stuffed
with BBC monographs and I have access online to Bell Labs Journal,
Philips Techinical Review and hundreds of individual publications. In addition to all that, I make contact with a network of other
transcription engineers and record collectors; we bounce problems back
and forth, trying to find explanations for observed phenomena.
Computers help with the communication but they haven't shown any signs
of doing the sort of thinking required for that kind of research.
So, you start with a piece of vinyl? And, end up with...?
Start with a piece of shellac-slate compound, laminated shellac, nitrate >>> on glass, nitrate on aluminium, gelatine on glass, gelatine on
cardboard, cellophane on cardboard, embossed solid aluminium,
chalk-filled vinyl (horribly noisy) - and, very rarely, vinyl itself.
The output is a computer file in AIFF which I record to a CDR for the
customer. Increasingly, customers are asking for the files on a USB
memory stick in various formats, presumably so they can erase them by
accident and expect me to provide another copy a few months later.
Well, you could claim that you don't keep copies of their COPYRIGHTED
materials...
The magic word is "DEEMED".
Lots of copyright material is stored illegally by any responsible
recording engineer, it is deemed not to exist and could not be found by
a casual search. If the circumstances change so that the recovery of a
lost gem becomes more important than its copyright status, it can be 'discovered' in some non-attributable way.
That is how many 'lost' radio programmes have come to light.
So, why not guesstimate the likely failure rate in the anticipated
work interval. Double that -- and maybe double it again. Buy that
many spares of the "essential components" and be done with it?
That is what I have done with my Mac G3s that run my business - but
buying oscilloscope tubes in quantity doesn't seem to be possible
nowadays. I can pick up a few on the secondhand market, but they are
all different.
Aside from being dropped or "mechanically insulted", what failure modes
are typical?
And, are the electrical differences so dramatic that you couldn't
accommodate them in the hardware design? The *mechanical* differences
could likely be accommodated (at some future effort) just by leaving sufficient space (volume) for the variations.
If my goal was to "replace you" (because your skillset was deemed valuable and you were exiting the workforce), I would design an AI and train it
by deliberately creating recordings with each of these "problems" you
have described.
[...]Another example: The X-Y display showed strange looping behaviour
There are hundreds of examples like this, each one unique.
And, yet, as mere mortals with infinite (expensive) time, you were
able to sort them out. Imagine what a machine with many times your
abilities could do!
I have tried to teach several people over the years but they soon loose interest. Many of them don't have enough basic knowledge of physics/ electronics/ engineering to understand the problems and, as long as they can do a quick-fix based on hearsay, they don't want to learn. Nowadays most people believe that digital can fix everything.
Machines don't have interest to lose. They pursue the goal set in front
of them. The human "trainers" are then the weakest link in the process;
in the variety of sample material they can present to the AI.
Lots of copyright material is stored illegally by any responsible
recording engineer, it is deemed not to exist and could not be found by
a casual search. If the circumstances change so that the recovery of a lost gem becomes more important than its copyright status, it can be 'discovered' in some non-attributable way.
That is how many 'lost' radio programmes have come to light.
But there is no obligation for YOU to continue that practice.
If my goal was to "replace you" (because your skillset was deemed valuable >> and you were exiting the workforce), I would design an AI and train it
by deliberately creating recordings with each of these "problems" you
have described.
...but that would only solve the problems we already know about. You couldn't train it to identify problems that might be encountered in
future and work out their causes, because you don't know what they might
be.
Why do certain recordings have a muffled 'boing' sound about 2 revs
before the music starts? Is it due to the electrodes in a valve in one
of the amplifiers expanding? Is it because the mastering studio used a Ferrograph with a clutch plate that magnetically snapped onto the HT
choke and the shock wave vibrated the EF86 in the head amplifier? Is it because there were springs in the scrolling mechanism that were
shock-excited as the mechanism disengaged.? Was it the sound of the
switch controlling the 'start' light in the studio? Was it some
accoutrement on the performer's clothing as they took a deep breath to
begin singing? Could it have been all of these on different recordings
at different times?
You couldn't train AI to 'envisage' all those possibilities unless you
could set up a series of recording studios exactly duplicating the
equipment, people and knowledge in use at each date - right down to the
sort of clothing and accessories a performer might wear. Is the
question important enough to justify this? Perhaps it would be if you
needed to verify the provenance of a potentially valuable historic
recording that claims to have been recently discovered but might be a
fake.
[...]Another example: The X-Y display showed strange looping behaviour
There are hundreds of examples like this, each one unique.
And, yet, as mere mortals with infinite (expensive) time, you were
able to sort them out. Imagine what a machine with many times your
abilities could do!
As far as I can see, it wouldn't do anything because it would take
longer to build and train than a group of us took to solve the problem - along with many other problems during the same period (e.g. Is the
locked groove always exactly the same diameter? Is the pitch of the
scroll significant? What are we having for supper tonight?)
I have tried to teach several people over the years but they soon loose
interest. Many of them don't have enough basic knowledge of physics/
electronics/ engineering to understand the problems and, as long as they >>> can do a quick-fix based on hearsay, they don't want to learn. Nowadays >>> most people believe that digital can fix everything.
Machines don't have interest to lose. They pursue the goal set in front
of them. The human "trainers" are then the weakest link in the process;
in the variety of sample material they can present to the AI.
Send me a machine that has passed exams in physics, electronic,
electrical and mechanical engineering, that can solder-up circuits to
test ideas and can make replacements for missing bits of mechanism on a worn-out lathe and search-out and interpret historical information from inaccurate sources ...and I will try to train it.
Lots of copyright material is stored illegally by any responsible
recording engineer, it is deemed not to exist and could not be found by
a casual search. If the circumstances change so that the recovery of a
lost gem becomes more important than its copyright status, it can be
'discovered' in some non-attributable way.
That is how many 'lost' radio programmes have come to light.
But there is no obligation for YOU to continue that practice.
There is a moral obligation as an historian.
There is also a practical reason: I go to a lot of trouble to 'rescue' a recording and then give the results of my labours to a customer who will
just as likely accidentally delete the files in six months time. A
second attempt to recover the sound from the originals will take a lot
more effort because they deteriorate each time they are played - and
that is if the customer hasn't thrown them away in the meantime.
Doesn't it make sense to keep a copy?
Then I guess you will have to accept limited spares availability and increased product size.
On 15/07/2025 10:12 pm, Don Y wrote:
Then I guess you will have to accept limited spares availability and
increased product size.
To be fair, I would rate the chance of obtaining in 30 years' time an exact replacement of some specific LCD oscilloscope originally obtained in 2025 from
aliexpress considerably lower than the chances of obtaining a spare tube for a
1960s CRT oscilloscope. Ditto the chances of fixing any fault in the support circuitry. If the LCD one is reliable enough to never ever fail, and its flash
memory retains the firmware long enough, then it might not matter.
On 15/07/2025 10:12 pm, Don Y wrote:
Then I guess you will have to accept limited spares availability and increased product size.
To be fair, I would rate the chance of obtaining in 30 years' time an
exact replacement of some specific LCD oscilloscope originally obtained
in 2025 from aliexpress considerably lower than the chances of obtaining
a spare tube for a 1960s CRT oscilloscope. ...
Chris Jones <lugnut808@spam.yahoo.com> wrote:
On 15/07/2025 10:12 pm, Don Y wrote:
Then I guess you will have to accept limited spares availability and
increased product size.
To be fair, I would rate the chance of obtaining in 30 years' time an
exact replacement of some specific LCD oscilloscope originally obtained
in 2025 from aliexpress considerably lower than the chances of obtaining
a spare tube for a 1960s CRT oscilloscope. ...
In 30 years time I shan't be here to worry about it but I agree that
older general-purpose components may still be available long after
'trendy' specialist ones have slipped into oblivion.
The chances of finding anyone who can repair anything to component level
will be much less in 30 years time than they already are. People who
can redesign circuity to suit a different CRT will be as rare in those
days as the people who can design steam engines are nowadays. (There
are people with the machining skills to copy existing designs, but how
many people actually understand the design process?)
Chris Jones <lugnut808@spam.yahoo.com> wrote:
On 15/07/2025 10:12 pm, Don Y wrote:
Then I guess you will have to accept limited spares availability and
increased product size.
To be fair, I would rate the chance of obtaining in 30 years' time an
exact replacement of some specific LCD oscilloscope originally obtained
in 2025 from aliexpress considerably lower than the chances of obtaining
a spare tube for a 1960s CRT oscilloscope. ...
In 30 years time I shan't be here to worry about it but I agree that
older general-purpose components may still be available long after
'trendy' specialist ones have slipped into oblivion.
The chances of finding anyone who can repair anything to component level
will be much less in 30 years time than they already are. People who
can redesign circuity to suit a different CRT will be as rare in those
days as the people who can design steam engines are nowadays. (There
are people with the machining skills to copy existing designs, but how
many people actually understand the design process?)
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
Chris Jones <lugnut808@spam.yahoo.com> wrote:
On 15/07/2025 10:12 pm, Don Y wrote:
Then I guess you will have to accept limited spares availability and
increased product size.
To be fair, I would rate the chance of obtaining in 30 years' time an
exact replacement of some specific LCD oscilloscope originally obtained
in 2025 from aliexpress considerably lower than the chances of obtaining >>> a spare tube for a 1960s CRT oscilloscope. ...
In 30 years time I shan't be here to worry about it but I agree that
older general-purpose components may still be available long after
'trendy' specialist ones have slipped into oblivion.
The chances of finding anyone who can repair anything to component level
will be much less in 30 years time than they already are. People who
can redesign circuity to suit a different CRT will be as rare in those
days as the people who can design steam engines are nowadays. (There
are people with the machining skills to copy existing designs, but how
many people actually understand the design process?)
Just a fyi fact we discovered on Friday: the $300 Siglent scope we recently bought for a road trip has XY mode.
I wonder what sample rate, and whether it displays all samples from the ADC. I
suspect it might capture a buffer full of 2 channels, diplay that, then capture
another buffer full, display that etc. and perhaps only be capturing a small percentage of the time.
https://www.youtube.com/watch?v=1tTeXPmbxW0
I think the situation with a phonograph record would be worse because the signal doesn't repeat, so if you miss something, you missed it.
At 100KS/s for a pair of 16 bit samples, you get 5 seconds per megabyte.
5000 seconds per gigabyte. How tightly coupled does the display *need*
to be to reality (or, is that just a legacy requirement)?
On 21/07/2025 11:11 pm, Phil Hobbs wrote:
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
Chris Jones <lugnut808@spam.yahoo.com> wrote:
On 15/07/2025 10:12 pm, Don Y wrote:
Then I guess you will have to accept limited spares availability and >>>> increased product size.
To be fair, I would rate the chance of obtaining in 30 years' time an
exact replacement of some specific LCD oscilloscope originally obtained >>> in 2025 from aliexpress considerably lower than the chances of obtaining >>> a spare tube for a 1960s CRT oscilloscope. ...
In 30 years time I shan't be here to worry about it but I agree that
older general-purpose components may still be available long after
'trendy' specialist ones have slipped into oblivion.
The chances of finding anyone who can repair anything to component level >> will be much less in 30 years time than they already are. People who
can redesign circuity to suit a different CRT will be as rare in those
days as the people who can design steam engines are nowadays. (There
are people with the machining skills to copy existing designs, but how
many people actually understand the design process?)
Just a fyi fact we discovered on Friday: the $300 Siglent scope we recently bought for a road trip has XY mode.
I wonder what sample rate, and whether it displays all samples from the
ADC. I suspect it might capture a buffer full of 2 channels, diplay
that, then capture another buffer full, display that etc. and perhaps
only be capturing a small percentage of the time.
https://www.youtube.com/watch?v=1tTeXPmbxW0
I think the situation with a phonograph record would be worse because
the signal doesn't repeat, so if you miss something, you missed it.
On 7/21/2025 5:16 PM, Chris Jones wrote:
I wonder what sample rate, and whether it displays all samples from
the ADC. I suspect it might capture a buffer full of 2 channels,
diplay that, then capture another buffer full, display that etc. and
perhaps only be capturing a small percentage of the time.
https://www.youtube.com/watch?v=1tTeXPmbxW0
I think the situation with a phonograph record would be worse because
the signal doesn't repeat, so if you miss something, you missed it.
Would your *eye* have caught it? Would you have been able to otherwise *react* to it -- given that you'd have to replay that part of the
media to recreate the event of interest?
Depending on bandwidth and gain(s), you are only plotting a few points
(a line segment from "last sample-pair to present sample-pair") in
each sample interval -- and unplotting the oldest such points in
your display list. A lot would depend on the thickness of the various
pipes (to display, memory, etc.). But, presumably, one could design
the hardware with that in mind.
Adding "effects" like persistence, antialiasing, highlights, variable
gain regions, etc. would complicate this. But, tomorrows hardware
would be twice as performant.
At 100KS/s for a pair of 16 bit samples, you get 5 seconds per megabyte.
5000 seconds per gigabyte. How tightly coupled does the display *need*
to be to reality (or, is that just a legacy requirement)?
You can also preprosess a lot of the math so you're just doing
fixed binary point math (Q<something>) in each mapping to the
display space.
There are several "oscilloscope for PC" packages out there that one
could examine as to performance. But, that would be running on highly performant hardware.
On 22/07/2025 10:57 am, Don Y wrote:
On 7/21/2025 5:16 PM, Chris Jones wrote:
I wonder what sample rate, and whether it displays all samples from the ADC.
I suspect it might capture a buffer full of 2 channels, diplay that, then >>> capture another buffer full, display that etc. and perhaps only be capturing
a small percentage of the time.
https://www.youtube.com/watch?v=1tTeXPmbxW0
I think the situation with a phonograph record would be worse because the >>> signal doesn't repeat, so if you miss something, you missed it.
Would your *eye* have caught it? Would you have been able to otherwise
*react* to it -- given that you'd have to replay that part of the
media to recreate the event of interest?
Depending on bandwidth and gain(s), you are only plotting a few points
(a line segment from "last sample-pair to present sample-pair") in
each sample interval -- and unplotting the oldest such points in
your display list. A lot would depend on the thickness of the various
pipes (to display, memory, etc.). But, presumably, one could design
the hardware with that in mind.
Adding "effects" like persistence, antialiasing, highlights, variable
gain regions, etc. would complicate this. But, tomorrows hardware
would be twice as performant.
At 100KS/s for a pair of 16 bit samples, you get 5 seconds per megabyte.
5000 seconds per gigabyte. How tightly coupled does the display *need*
to be to reality (or, is that just a legacy requirement)?
You can also preprosess a lot of the math so you're just doing
fixed binary point math (Q<something>) in each mapping to the
display space.
There are several "oscilloscope for PC" packages out there that one
could examine as to performance. But, that would be running on highly
performant hardware.
Oh yes, there are people who know how to make beautiful emulations of CRT displays:
https://www.windytan.com/2013/03/rendering-pcm-with-simulated-phosphor.html
https://www.youtube.com/watch?v=ozRZ_q_FbqU
You won't get that from an affordable DSO though, and definitely not in real time. Maybe if there were a market for it, it would happen eventually. For the
OP's problem, at least the bandwidth is low, so a PC sound card and modern GPU
ought to be able to handle it with the right software, and if the PC were already there anyway then it might be a good solution, but it isn't so it's not.
I want to incorporate an oscilloscope display in a piece of equipment.
I asked about this here some time ago but there didn't seem to be
anything on the market at that time that met my requirements. I am
wondering if anyone has come across something since I last asked.
The need is for an X-Y display with a bandwidth of 100 Kc/s on each
channel and no significant lag. It will be working with signals of
around 1v rms but a higher voltage could be supplied if necessary. It
must boot up automatically on power-up, with no menus or user
intervention and must always return to its previous settings.
The screen needs to be about 4" diagonal with very fine resolution (particularly at the centre), green, white or blue trace would be
acceptable but multi-colour is not necessary. If it is susceptible to screen-burn from a stationary spot, DC-coupled Z-mod will be needed.
I do not want to have to learn to program a microprocessor in order to
use it.
Chris Jones <lugnut808@spam.yahoo.com> wrote:
On 22/07/2025 10:57 am, Don Y wrote:
On 7/21/2025 5:16 PM, Chris Jones wrote:
I wonder what sample rate, and whether it displays all samples from
the ADC. I suspect it might capture a buffer full of 2 channels,
diplay that, then capture another buffer full, display that etc. and
perhaps only be capturing a small percentage of the time.
https://www.youtube.com/watch?v=1tTeXPmbxW0
I think the situation with a phonograph record would be worse because
the signal doesn't repeat, so if you miss something, you missed it.
Would your *eye* have caught it? Would you have been able to otherwise >>> *react* to it -- given that you'd have to replay that part of the
media to recreate the event of interest?
Depending on bandwidth and gain(s), you are only plotting a few points
(a line segment from "last sample-pair to present sample-pair") in
each sample interval -- and unplotting the oldest such points in
your display list. A lot would depend on the thickness of the various
pipes (to display, memory, etc.). But, presumably, one could design
the hardware with that in mind.
Adding "effects" like persistence, antialiasing, highlights, variable
gain regions, etc. would complicate this. But, tomorrows hardware
would be twice as performant.
At 100KS/s for a pair of 16 bit samples, you get 5 seconds per megabyte. >>> 5000 seconds per gigabyte. How tightly coupled does the display *need* >>> to be to reality (or, is that just a legacy requirement)?
You can also preprosess a lot of the math so you're just doing
fixed binary point math (Q<something>) in each mapping to the
display space.
There are several "oscilloscope for PC" packages out there that one
could examine as to performance. But, that would be running on highly
performant hardware.
Oh yes, there are people who know how to make beautiful emulations of
CRT displays:
https://www.windytan.com/2013/03/rendering-pcm-with-simulated-phosphor.html >>
https://www.youtube.com/watch?v=ozRZ_q_FbqU
You won't get that from an affordable DSO though, and definitely not in
real time. Maybe if there were a market for it, it would happen
eventually. For the OP's problem, at least the bandwidth is low, so a PC
sound card and modern GPU ought to be able to handle it with the right
software, and if the PC were already there anyway then it might be a
good solution, but it isn't so it's not.
Sampling at 1 MS/sec (should be enough for 100 KHz signal) and
assuming decay in 1s gives 1 mln points for display. For
each point one needs to apply decay factor and redistribute value
betwen corresponding points,
I would expect about 40 machine
instructions per sample. One needs to do this for each frame,
assuming 30 frames per second this gives 1200 mln instrucions
per second. Quite doable on Raspbery Pi class board. This assumes
doing computation via CPU. For video core in Raspbery Pi this
should be very easy job. Smaller RPi class boards can fit
behind 10cm by 10 cm screen, so size should not be a problem.
On 01/08/2025 01:57, Don Y wrote:
"Pause. Backup 3 seconds and lets see that again.
Tweak the gain. Once more... Compare this portion
to this OTHER portion I marked, earlier -- superimposed
or split screen, etc"
I think the point is that the mechanical arrangement needs to be interactively
adjusted before a good quality capture can happen.
Things like stylus dimensions, tracking force and arm geometry
were mentioned earlier.
On 7/31/2025 5:27 PM, Waldek Hebisch wrote:
Chris Jones <lugnut808@spam.yahoo.com> wrote:
On 22/07/2025 10:57 am, Don Y wrote:
On 7/21/2025 5:16 PM, Chris Jones wrote:
I wonder what sample rate, and whether it displays all samples from
the ADC. I suspect it might capture a buffer full of 2 channels,
diplay that, then capture another buffer full, display that etc. and >>>>> perhaps only be capturing a small percentage of the time.
https://www.youtube.com/watch?v=1tTeXPmbxW0
I think the situation with a phonograph record would be worse because >>>>> the signal doesn't repeat, so if you miss something, you missed it.
Would your *eye* have caught it? Would you have been able to otherwise >>>> *react* to it -- given that you'd have to replay that part of the
media to recreate the event of interest?
Depending on bandwidth and gain(s), you are only plotting a few points >>>> (a line segment from "last sample-pair to present sample-pair") in
each sample interval -- and unplotting the oldest such points in
your display list. A lot would depend on the thickness of the various >>>> pipes (to display, memory, etc.). But, presumably, one could design
the hardware with that in mind.
Adding "effects" like persistence, antialiasing, highlights, variable
gain regions, etc. would complicate this. But, tomorrows hardware
would be twice as performant.
At 100KS/s for a pair of 16 bit samples, you get 5 seconds per megabyte. >>>> 5000 seconds per gigabyte. How tightly coupled does the display *need* >>>> to be to reality (or, is that just a legacy requirement)?
You can also preprosess a lot of the math so you're just doing
fixed binary point math (Q<something>) in each mapping to the
display space.
There are several "oscilloscope for PC" packages out there that one
could examine as to performance. But, that would be running on highly >>>> performant hardware.
Oh yes, there are people who know how to make beautiful emulations of
CRT displays:
https://www.windytan.com/2013/03/rendering-pcm-with-simulated-phosphor.html >>>
https://www.youtube.com/watch?v=ozRZ_q_FbqU
You won't get that from an affordable DSO though, and definitely not in
real time. Maybe if there were a market for it, it would happen
eventually. For the OP's problem, at least the bandwidth is low, so a PC >>> sound card and modern GPU ought to be able to handle it with the right
software, and if the PC were already there anyway then it might be a
good solution, but it isn't so it's not.
Sampling at 1 MS/sec (should be enough for 100 KHz signal) and
assuming decay in 1s gives 1 mln points for display. For
each point one needs to apply decay factor and redistribute value
betwen corresponding points,
Depending on the nature of the effect, you may involve more
than the sampled number of points. E.g., at high intensities,
a CRT phosphor may appear to "bloom" into adjacent points on
the display; points that don't directly correspond to sampled
data.
But, you only need to update the "effect" at a fast enough rate to
not be detectable by the vision system; the first *group* of
data points will all appear at the same "effect level", even
though they were sampled many microseconds apart, in time.
How you "paint" this onto the display depends on what the
display interface model looks like; the bits don't just
magically and instantaneously render pels on the display.
And, of course, the timing of accesses to that "memory space"
can impact how quickly a dot can be updated. This may be slower
than updating bits in general purpose memory.
I would expect about 40 machine
instructions per sample. One needs to do this for each frame,
assuming 30 frames per second this gives 1200 mln instrucions
per second. Quite doable on Raspbery Pi class board. This assumes
doing computation via CPU. For video core in Raspbery Pi this
should be very easy job. Smaller RPi class boards can fit
behind 10cm by 10 cm screen, so size should not be a problem.
I don't understand why one wouldn't want to CAPTURE the entire
RAW signal -- playing the original medium exactly once -- and
then experimenting with the captured data. Applying post
processing to *it* instead of trying to tweek that while
the original medium is being subjected to mechanical playback
action.
But, you only need to update the "effect" at a fast enough rate to
not be detectable by the vision system; the first *group* of
data points will all appear at the same "effect level", even
though they were sampled many microseconds apart, in time.
There are many tricks which one could try to speed up display.
Details should be worked out when doing actual implementation.
My point was that implementation is feasible on available
machines.
How you "paint" this onto the display depends on what the
display interface model looks like; the bits don't just
magically and instantaneously render pels on the display.
For such level of visual detail one needs multiple buffered display,
drawing to memory buffer. This may involve copy from computer
RAM to video memory. While such copy have non-trival cost,
needed time is still smaller than time for computation.
And, of course, the timing of accesses to that "memory space"
can impact how quickly a dot can be updated. This may be slower
than updating bits in general purpose memory.
Well, if display can not update fast, then there is no point in
higher fram rates, just lower frame rate to what display can do,
I would expect about 40 machine
instructions per sample. One needs to do this for each frame,
assuming 30 frames per second this gives 1200 mln instrucions
per second. Quite doable on Raspbery Pi class board. This assumes
doing computation via CPU. For video core in Raspbery Pi this
should be very easy job. Smaller RPi class boards can fit
behind 10cm by 10 cm screen, so size should not be a problem.
I don't understand why one wouldn't want to CAPTURE the entire
RAW signal -- playing the original medium exactly once -- and
then experimenting with the captured data. Applying post
processing to *it* instead of trying to tweek that while
the original medium is being subjected to mechanical playback
action.
IIUC the point is that data captured with wrong settings is
essentially useless. I do not know what Liz is exactly doing,
but clearly want to monitor and adjust settings in real time.
There may be psychological effect: human brain is better at
finding dynamic changes than detail in static image.
I do not condider problem of automating what Liz is doing,
for some problem of related nature there are remarkable
successes, but also many problems currently lack cost-effective
solution.
Don Y <blockedofcourse@foo.invalid> wrote:
On 7/15/2025 2:33 AM, Liz Tuddenham wrote:
better. Many years ago I programmed a Z80 but that was for a particular >> > task that was best done that way. Whilst things like the Raspberry Pie
might be almost good enough for occasional specific needs (or they might >> > not), the effort involved in learning to use them and buying all the
peripherals to program them have never been worthwhile.
That's not a big cost, nowadays. I recall paying $15K for a Unisite,
$25K for (each of several) ICEs, etc.
Those prices are completely beyond anything I could afford. All my
equipment put together hasn't cost that much.
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
Don Y <blockedofcourse@foo.invalid> wrote:
On 7/15/2025 2:33 AM, Liz Tuddenham wrote:
better. Many years ago I programmed a Z80 but that was for a particular >>>> task that was best done that way. Whilst things like the Raspberry Pie >>>> might be almost good enough for occasional specific needs (or they might >>>> not), the effort involved in learning to use them and buying all the
peripherals to program them have never been worthwhile.
That's not a big cost, nowadays. I recall paying $15K for a Unisite,
$25K for (each of several) ICEs, etc.
Those prices are completely beyond anything I could afford. All my
equipment put together hasn't cost that much.
The prices Don gave are _old_ prices.
Now instead of Z80 one can use
Arduino, below 4$ you can get a board and USB cable. Assuming that
you have a computer that is all hardware to get started. I like
Blue Pils (based on STM32), which are even cheaper than Arduino
hardware and more powerful, but there is less support on the net
for them. There are a bit more powerful STM32-based board at about
4-5$. For STM-32 board you probably want STLINK debugging dongle
which adds something like 2$. There are ESP board and Raspberry Pi
Pico, each for few dolars. The above are microcontoller board,
for more processing power (and HDMI interface to display) one
can get one of single-board computers. To get started you need
such board and a SD-card. Small boards are available below 20$,
small SD-card can cost 2.5$.
Just a little comment: if you need to generate or scan fast
digital signals on processor pins, than microcontrollers are
in practice faster. OTOH if you need number crunching and
say have external source of data like reasonably fast ADC, then
single-board computers will win.
Also another comment: programming processor can be done using
very little extra hardware (beyond a computer). Many microcontrollers
come with "bootloader" in "ROM". When you connect few pins
in a special way and turn on the power, bootloader will start
and wait for program on say serial port. So USB to serial
convertor (available below 2$) and approiate program on the
computer is enough to program the chip. Arduino hardware do
not have bootloader in ROM, but when you buy a board it will
typically come with bootloader burned at start of the flash.
And typical Arduino board have USB to serial convertor on
the board, so you can program the board from you computer
via USB cable. Raspbery Pi Pico contains bootloader which
emulates a hard disk. If you copy a file with magic name
to this "disk" the effect is to program the chip. Debugging
dongles, like STLINK for STM32 chips also support programming.
Above is stuff meant mainly for hobby, but useful also for
professionals. If you want to go with stuff blessed by
processor manufactures, then there are various developement
boards at prices below 20$. You may want Segger debugging
dongle which you probably can get below 100$. Osciloscope
with bandtwith of 100 MHz or better can sometimes help
(but most of the time information collected by programs
is enough to resolve problems).
For your audio work you may want fast high resolution ADC,
those may be expensive (they are defintely too expensive for
me to buy them just for occasional playing).
Of course, beside hardware cost, which may be quite low there
is also time. Here much depends on what level you want to
work. Arduino may be limiting, but one can do simple things
pretty quickly. Manufactures typically provide support libraries
and examples, they can save a lot of work. Or you may wish/need
to work directly with the chips, expect hundreds of pages of
documentation to read in such case.
Sampling at 1 MS/sec (should be enough for 100 KHz signal) and
assuming decay in 1s gives 1 mln points for display. For
each point one needs to apply decay factor and redistribute value
betwen corresponding points, I would expect about 40 machine
instructions per sample.
One needs to do this for each frame,
assuming 30 frames per second this gives 1200 mln instrucions
per second. Quite doable on Raspbery Pi class board. This assumes
doing computation via CPU. For video core in Raspbery Pi this
should be very easy job. Smaller RPi class boards can fit
behind 10cm by 10 cm screen, so size should not be a problem.
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