OT - CRT's

On Tuesday, 21 May 2019 12:58:13 UTC+1, Bob Engelhardt wrote:
> Is there still a use for CRT's?

Collectors are one market of course. There's also testgear that incorporated CRTs, other than silly scopes.


NT

 

[Chris Jones]

On 21/05/2019 21:57, Bob Engelhardt wrote:
> Is there still a use for CRT's?

They collect radioactive dust (I think polonium that results from the
decay of radon) out of the air (it seems to be charged).

If you wipe the entire face of a CRT that has been used a lot recently,
with a tissue (preferably held in such a way that the dust all collects
in a small area of the tissue) then hold this dust in front of a geiger
counter, it will be quite noticably radioactive.

By collecting this radioactive dust out of the air, some of it will be
prevented from lodging in my lungs.

I suspect that the replacement of CRTs with LCDs in households will
eventually result in an increase in lung cancer, though probably only a
small one that may be masked by other changes over the years such as
vehicle emissions.

Here is some info about the dust:
http://www.techlib.com/science/secondhandsmoke.htm

 

[George Herold]

On Tuesday, May 21, 2019 at 11:41:18 PM UTC-4, whit3rd wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on vertical/horizontal matching, which an LCD
cannot provide, at rates that a 'video' screen cannot update. That kind of display
does NOT function well with digitization. Clocking very much gets in the way of
the function.

Everything that digital does for you, it also does TO you.

The new Keysight infivision 'scopes do a great job at X-Y.

Clean and fast...

George H.

 

[John Larkin]

On Tue, 21 May 2019 23:27:25 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Tuesday, May 21, 2019 at 10:33:05 PM UTC-7, Tim Williams wrote:
"whit3rd" <whit3rd@gmail.com> wrote in message
news:56bc7695-c7fe-4abc-9a14-b243cd975c62@googlegroups.com...
On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:

Yes. Lissajous figures, after all, depend on vertical/horizontal
matching, which an LCD
cannot provide, at rates that a 'video' screen cannot update.

That's an old-fashioned opinion even for a /newsgroup/. Lissajous figures
disappeared in the late 30s as synced/triggered sweep took over.

Finding out if two oscillators are locked, it's handy.
There's some modern work on the subject:

https://youtu.be/rtR63-ecUNo

It's fun to connect two good oscillators to a dual-trace scope. Say a
rubidium and a caesium or GPS. Trigger on one and look at both. Sweep
maybe 10 ns/div. Check every few hours and see if anything has moved.

Infinite persistance is useful for a lot of time and jitter
measurements. Analog storage scopes were really awful.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Wed, 22 May 2019 00:33:51 -0500, "Tim Williams"
<tiwill@seventransistorlabs.com> wrote:

"whit3rd" <whit3rd@gmail.com> wrote in message
news:56bc7695-c7fe-4abc-9a14-b243cd975c62@googlegroups.com...
On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on vertical/horizontal
matching, which an LCD
cannot provide, at rates that a 'video' screen cannot update.

That's an old-fashioned opinion even for a /newsgroup/. Lissajous figures
disappeared in the late 30s as synced/triggered sweep took over. Combined
with how not-very-useful they are, it strains the imagination to believe
anyone here has actually, usefully, unironically used them. ;-)

Tim

When I was a kid, I'd set up a Lissajous display at parties. Yes, I
was a geek even then.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Wed, 22 May 2019 07:18:00 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Tue, 21 May 2019 21:56:46 -0700 (PDT)) it happened whit3rd
whit3rd@gmail.com> wrote in
a28b4b34-43a5-4491-b6f4-d138f8fa3c92@googlegroups.com>:

On Tuesday, May 21, 2019 at 9:15:20 PM UTC-7, Steve Wilson wrote:
whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figure...

Everything that digital does for you, it also does TO you.

Lissajous figures require sine waves. Doesn't work with pulses, square waves,
etc.

Moden method: Display a few cycles of one signal, trigger on the other. You
can get much finer resolution than provided by Lissajous figures, and track
very small phase changes over hours or days. You can measure the offset
directly in picoseconds or whatever is appropriate. This is difficult or
impossible to do with Lissajous figures.

The trigger is an ASYNCHRONOUS event, but its capture by a DSO is typically
a SYNCHRONOUS event, happening on a clock edge. That's not good
for accurate timing. Digtization hurts the process.

A knob adjustment while watching a Lissajous pattern is a lot quicker than
'measure the offset directly' will ever be. The pattern dynamics is a
quicker informant than a digital readout for a human interface.

I've watched audio assembly-line workers, with a test generator putting up
a dozen patterns (for half a second each); they knew exactly what to adjust
and got to their goal in seconds. Probably, for audio, digital timing wasn't
a problem, of course.

mm
yes,
but I am playing with an audio narrow band 90 degrees phase shift network,
and on my analog scope a circle is not enough to measure how many degrees it is off.
Analog scopes have distortion and gain differences between channels too.
So back to the analyzer...

We make an I-Q modulator box that works in the 10s of MHz. One
production test will verify the 90 degree channel. We'll use a 500 MHz
Rigol scope and automate the testing. It will measure the phase shift
accurately if we're careful about the cable time delays.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Tue, 21 May 2019 21:56:46 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Tuesday, May 21, 2019 at 9:15:20 PM UTC-7, Steve Wilson wrote:
whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figure...

Everything that digital does for you, it also does TO you.

Lissajous figures require sine waves. Doesn't work with pulses, square waves,
etc.

Moden method: Display a few cycles of one signal, trigger on the other. You
can get much finer resolution than provided by Lissajous figures, and track
very small phase changes over hours or days. You can measure the offset
directly in picoseconds or whatever is appropriate. This is difficult or
impossible to do with Lissajous figures.

The trigger is an ASYNCHRONOUS event, but its capture by a DSO is typically
a SYNCHRONOUS event, happening on a clock edge. That's not good
for accurate timing. Digtization hurts the process.

Our usual bench digital scopes can measure edge timings to 30
picoseconds, and the big LeCroy gets below 1 ps, with 1 ps RMS jitter.

Look up "the sampling theorem." One can accurately measure times to a
very small fraction of the scope's sampling rate.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Wed, 22 May 2019 04:49:14 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

Steve Wilson <no@spam.com> wrote in
news:XnsAA57296B863Eidtokenpost@69.16.179.22:

whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on
vertical/horizontal matching, which an LCD cannot provide, at
rates that a 'video' screen cannot update. That kind of
display does NOT function well with digitization. Clocking very
much gets in the way of the function.

Everything that digital does for you, it also does TO you.

Lissajous figures require sine waves. Doesn't work with pulses,
square waves, etc.

Moden method: Display a few cycles of one signal, trigger on the
other. You can get much finer resolution than provided by
Lissajous figures, and track very small phase changes over hours
or days. You can measure the offset directly in picoseconds or
whatever is appropriate. This is difficult or impossible to do
with Lissajous figures.



One would have to use those old polaroid hoods for the scope and
take successive snapshots and then hand timestamp, measure and
analyse them. Yeah, sure...

With a digital scope, wait until you have a beautiful waveform, hit
STOP, and capture that for the manual.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Tue, 21 May 2019 20:41:14 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on vertical/horizontal matching, which an LCD
cannot provide, at rates that a 'video' screen cannot update. That kind of display
does NOT function well with digitization. Clocking very much gets in the way of
the function.

Everything that digital does for you, it also does TO you.

My digital scopes can do Lissajous figures in XY mode, but I never do
that. They can measure phase accurately.

A CRT can't really measure anything accurately.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Wed, 22 May 2019 11:39:32 +1000, Sylvia Else <sylvia@email.invalid>
wrote:

On 21/05/2019 9:57 pm, Bob Engelhardt wrote:
Is there still a use for CRT's?

Long lasting equipment?

I have scope from about 1985 that still works (did have to repair it
once, admittedly, and it hasn't seen that much use). Everything else
from that era is gone.

Sylvia.

All our analog scopes eventually died, the last one being the 1 GHz
Tek 7104, the one with the microchannel plate.

I don't think any of our digital scopes has ever failed.

The only thing I miss about analog scopes is the exotic plugins, the
super gain differential switchable-bandwidth things. Fabulous for
low-level stuff. You can buy external boxes that do most of that.




--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

John Larkin <jjlarkin@highlandtechnology.com> wrote in
news:a6maeetb6ir3gab7fabjbbfnauchls2lic@4ax.com:

On Tue, 21 May 2019 20:41:14 -0700 (PDT), whit3rd
whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on vertical/horizontal
matching, which an LCD cannot provide, at rates that a 'video'
screen cannot update. That kind of display does NOT function
well with digitization. Clocking very much gets in the way of
the function.

Everything that digital does for you, it also does TO you.

My digital scopes can do Lissajous figures in XY mode, but I never
do that. They can measure phase accurately.

A CRT can't really measure anything accurately.

They can 'tell you' if a tornado is approaching with the right
input setup.

 

[John Larkin]

On Wed, 22 May 2019 14:49:12 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Wed, 22 May 2019 07:27:29 -0700) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
ssmaeetvb3cnjhtoujqmlota57365s6r6i@4ax.com>:

On Wed, 22 May 2019 07:18:00 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Tue, 21 May 2019 21:56:46 -0700 (PDT)) it happened whit3rd
whit3rd@gmail.com> wrote in
a28b4b34-43a5-4491-b6f4-d138f8fa3c92@googlegroups.com>:

On Tuesday, May 21, 2019 at 9:15:20 PM UTC-7, Steve Wilson wrote:
whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figure...

Everything that digital does for you, it also does TO you.

Lissajous figures require sine waves. Doesn't work with pulses, square waves,
etc.

Moden method: Display a few cycles of one signal, trigger on the other. You
can get much finer resolution than provided by Lissajous figures, and track
very small phase changes over hours or days. You can measure the offset
directly in picoseconds or whatever is appropriate. This is difficult or
impossible to do with Lissajous figures.

The trigger is an ASYNCHRONOUS event, but its capture by a DSO is typically
a SYNCHRONOUS event, happening on a clock edge. That's not good
for accurate timing. Digtization hurts the process.

A knob adjustment while watching a Lissajous pattern is a lot quicker than
'measure the offset directly' will ever be. The pattern dynamics is a
quicker informant than a digital readout for a human interface.

I've watched audio assembly-line workers, with a test generator putting up
a dozen patterns (for half a second each); they knew exactly what to adjust
and got to their goal in seconds. Probably, for audio, digital timing wasn't
a problem, of course.

mm
yes,
but I am playing with an audio narrow band 90 degrees phase shift network,
and on my analog scope a circle is not enough to measure how many degrees it is off.
Analog scopes have distortion and gain differences between channels too.
So back to the analyzer...

We make an I-Q modulator box that works in the 10s of MHz. One
production test will verify the 90 degree channel. We'll use a 500 MHz
Rigol scope and automate the testing. It will measure the phase shift
accurately if we're careful about the cable time delays.

Yes, this one outputs 2.4 GHz
On the analyzer you can see carrier sideband and suppression down to about -50 dB,
sideband suppression should be maximum if the 90 degrees is correct.
I use fixed tones and frequency sweep 240 Hz to 2.4 kHz (audio range) I and Q
to drive an AD8346 QAM modulator directly at 2.4 GHz

Want to test some capacitors, ordered this from ebay yesterday:
https://www.ebay.com/itm/254207643325

Your fingers will add/change capacitance as you squeeze that.

My AADE meter came with a plug-in PC board that has a narrow gap in
the topside copper. I can zero the capacitance then bridge the gap
with a surface-mount cap, and push it down with the back end of a
wooden q-tip or a toothpick. That seems to be good for low-c caps.

I guess the real way to measure small caps would be to connect some
pcb pads to the meter, measure that, then solder in the cap and
measure again.

I could make a pc board to help doing that. Next proto board maybe.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

tabbypurr@gmail.com wrote in
news:5db584f9-e973-4158-b4de-374f15c45950@googlegroups.com:

On Tuesday, 21 May 2019 12:58:13 UTC+1, Bob Engelhardt wrote:
Is there still a use for CRT's?

Collectors are one market of course. There's also testgear that
incorporated CRTs, other than silly scopes.


NT

Finding replacements is the thing. They (lab gear) are typically NON
standard.

A good CRT maker still doing it is Thomas Electronics

<https://www.thomaselectronics.com/>

..

 

[George Herold]

On Wednesday, May 22, 2019 at 10:29:14 AM UTC-4, John Larkin wrote:

On Wed, 22 May 2019 00:33:51 -0500, "Tim Williams"
tiwill@seventransistorlabs.com> wrote:

"whit3rd" <whit3rd@gmail.com> wrote in message
news:56bc7695-c7fe-4abc-9a14-b243cd975c62@googlegroups.com...
On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on vertical/horizontal
matching, which an LCD
cannot provide, at rates that a 'video' screen cannot update.

That's an old-fashioned opinion even for a /newsgroup/. Lissajous figures
disappeared in the late 30s as synced/triggered sweep took over. Combined
with how not-very-useful they are, it strains the imagination to believe
anyone here has actually, usefully, unironically used them. ;-)

Tim

When I was a kid, I'd set up a Lissajous display at parties. Yes, I
was a geek even then.

You too? I'd hook up the right speaker to one chan, and left to other.
(That was in grad school, once I'd scored a free 'scope from the
physics department.)
(I seem to recall having some issues with how ground was attached.)
Hey these days it would be fun to have a DSO show the time and
frequency domain.

George H.

--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Joerg]

On 2019-05-21 04:57, Bob Engelhardt wrote:

Is there still a use for CRT's?

Yes, in oscilloscopes. There is stuff that cannot be properly detected
on a digital oscilloscope, especially when it comes to random noise from
sources whose noise pattern isn't known a priori. The jobs where you
have to see "fuzz on fuzz" and sometimes figure out a pattern in the
unwanted fuzz to find out where that comes from. Many times I have
dragged an old analog scope scope from a client's clutter cabinet, did a
quick emergency "resurrection" on it and found their problem. Other
times we did an EBay rush order for a Tektronix 2465 or similar.

You can still buy analog scopes, in part for the above reason. Iwatsu
makes high-end ones and lower cost versions can be found on Amazon.

https://www.iti.iwatsu.co.jp/en/products/ss/ss_top_e.html

https://www.amazon.com/dp/B00QXNY874

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Bill Sloman]

On Thursday, May 23, 2019 at 12:15:53 AM UTC+10, John Larkin wrote:

On Tue, 21 May 2019 20:41:14 -0700 (PDT), whit3rd <whit3rd@gmail.com
wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on vertical/horizontal matching, which an LCD
cannot provide, at rates that a 'video' screen cannot update. That kind of display
does NOT function well with digitization. Clocking very much gets in the way of
the function.

Everything that digital does for you, it also does TO you.

My digital scopes can do Lissajous figures in XY mode, but I never do
that. They can measure phase accurately.

A CRT can't really measure anything accurately.

It isn't the CRT doing the measurement, but the operator.

An operator who is aware of the limitations of the tools being used can get accurate results with quite crude tools, though they do tend to improve the tools to get more accurate results.

--
Bill Sloman, Sydney

 

[Jan Panteltje]

On a sunny day (Wed, 22 May 2019 07:27:29 -0700) it happened John Larkin
<jjlarkin@highlandtechnology.com> wrote in
<ssmaeetvb3cnjhtoujqmlota57365s6r6i@4ax.com>:

On Wed, 22 May 2019 07:18:00 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Tue, 21 May 2019 21:56:46 -0700 (PDT)) it happened whit3rd
whit3rd@gmail.com> wrote in
a28b4b34-43a5-4491-b6f4-d138f8fa3c92@googlegroups.com>:

On Tuesday, May 21, 2019 at 9:15:20 PM UTC-7, Steve Wilson wrote:
whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figure...

Everything that digital does for you, it also does TO you.

Lissajous figures require sine waves. Doesn't work with pulses, square waves,
etc.

Moden method: Display a few cycles of one signal, trigger on the other. You
can get much finer resolution than provided by Lissajous figures, and track
very small phase changes over hours or days. You can measure the offset
directly in picoseconds or whatever is appropriate. This is difficult or
impossible to do with Lissajous figures.

The trigger is an ASYNCHRONOUS event, but its capture by a DSO is typically
a SYNCHRONOUS event, happening on a clock edge. That's not good
for accurate timing. Digtization hurts the process.

A knob adjustment while watching a Lissajous pattern is a lot quicker than
'measure the offset directly' will ever be. The pattern dynamics is a
quicker informant than a digital readout for a human interface.

I've watched audio assembly-line workers, with a test generator putting up
a dozen patterns (for half a second each); they knew exactly what to adjust
and got to their goal in seconds. Probably, for audio, digital timing wasn't
a problem, of course.

mm
yes,
but I am playing with an audio narrow band 90 degrees phase shift network,
and on my analog scope a circle is not enough to measure how many degrees it is off.
Analog scopes have distortion and gain differences between channels too.
So back to the analyzer...

We make an I-Q modulator box that works in the 10s of MHz. One
production test will verify the 90 degree channel. We'll use a 500 MHz
Rigol scope and automate the testing. It will measure the phase shift
accurately if we're careful about the cable time delays.

Yes, this one outputs 2.4 GHz
On the analyzer you can see carrier sideband and suppression down to about -50 dB,
sideband suppression should be maximum if the 90 degrees is correct.
I use fixed tones and frequency sweep 240 Hz to 2.4 kHz (audio range) I and Q
to drive an AD8346 QAM modulator directly at 2.4 GHz

Want to test some capacitors, ordered this from ebay yesterday:
https://www.ebay.com/itm/254207643325

These SMDs 10nF 1% seem OK, and a lot smaller than the big 1% ones I have now:
https://www.reichelt.nl/multilayer-keramische-condensator-10nf-25v-125-c-kem-c0g0603-10n-p206974.html?&trstct=pos_11
maybe I will order some and select for close matches / lowest tolerance.
Not in a hurry, watching movies,...
Yes, that Rigol is attractive, and would also do fine for audio range phase shift measurements.
You could also do some zero crossing detection and set reset a flip-flop
by I and Q and measure its output pulse width for audio as value of the phase shift.

 

John Larkin <jjlarkin@highlandtechnology.com> wrote in
newsdmaeedm558b8t5871f0ma7m1hgg1fir5l@4ax.com:

On Wed, 22 May 2019 04:49:14 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

Steve Wilson <no@spam.com> wrote in
news:XnsAA57296B863Eidtokenpost@69.16.179.22:

whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin
wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on
vertical/horizontal matching, which an LCD cannot provide, at
rates that a 'video' screen cannot update. That kind of
display does NOT function well with digitization. Clocking
very
much gets in the way of the function.

Everything that digital does for you, it also does TO you.

Lissajous figures require sine waves. Doesn't work with pulses,
square waves, etc.

Moden method: Display a few cycles of one signal, trigger on the
other. You can get much finer resolution than provided by
Lissajous figures, and track very small phase changes over hours
or days. You can measure the offset directly in picoseconds or
whatever is appropriate. This is difficult or impossible to do
with Lissajous figures.



One would have to use those old polaroid hoods for the scope and
take successive snapshots and then hand timestamp, measure and
analyse them. Yeah, sure...

With a digital scope, wait until you have a beautiful waveform,
hit
STOP, and capture that for the manual.

It was a joke, Johnny. Those of us in the discussion... it is a
good bet that we all know what a DSO is,

 

[John Larkin]

On Wed, 22 May 2019 15:41:14 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

tabbypurr@gmail.com wrote in
news:5db584f9-e973-4158-b4de-374f15c45950@googlegroups.com:

On Tuesday, 21 May 2019 12:58:13 UTC+1, Bob Engelhardt wrote:
Is there still a use for CRT's?

Collectors are one market of course. There's also testgear that
incorporated CRTs, other than silly scopes.


NT


Finding replacements is the thing. They (lab gear) are typically NON
standard.

A good CRT maker still doing it is Thomas Electronics

https://www.thomaselectronics.com/

.

I designed a vector character generator to upgrade the electronics on
the AH130 gunship. It drove a CRT heads-up display for the pilot. The
old electronics had an MTBF of 24 hours.

We did this:

simulated:

https://www.dropbox.com/s/b4cucv9kegt9vwe/GR8J_2us.jpg?dl=0

on a real CRT:

https://www.dropbox.com/s/mrwv2mfwujdu82l/GR8.jpg?dl=0

We sold some, but eventually they went LCD.



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Wed, 22 May 2019 15:43:44 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

John Larkin <jjlarkin@highlandtechnology.com> wrote in
news:a6maeetb6ir3gab7fabjbbfnauchls2lic@4ax.com:

On Tue, 21 May 2019 20:41:14 -0700 (PDT), whit3rd
whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on vertical/horizontal
matching, which an LCD cannot provide, at rates that a 'video'
screen cannot update. That kind of display does NOT function
well with digitization. Clocking very much gets in the way of
the function.

Everything that digital does for you, it also does TO you.

My digital scopes can do Lissajous figures in XY mode, but I never
do that. They can measure phase accurately.

A CRT can't really measure anything accurately.



They can 'tell you' if a tornado is approaching with the right
input setup.

I don't do tornados, and we don't have them here anyhow. I design
electronics, and a digital scope does the quantitative measurements
that I need.

Ancient video games and Lissajous figures are toys.

I'd expect that weather radar displays are all LCDs now anyhow.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics