OT - CRT's

John Robertson wrote in news: snipped-for-privacy@giganews.com:

Light gun games do not work with LCD displays because they are progressive scan devices. Maybe a couple other reasons.

I had a 37" CRT widescreen HDTV back in the first days of HDTV and it would not work wither becuase of the progressive scan. It tried and would catch shots sometimes, but generally failed.

John Robertson wrote in news: snipped-for-privacy@giganews.com:

Uh... It is 4:3 not 3:4.

And nearly ALL LCD display I am aware of will still render a 4:3 source. They simply do not "fill the screen" like so many layman TV watchers "must have" or they feel shorted. Not realizing that it was God whom shorted them on brain cells.

LCD works fine on game emulation short of the light gun variety. Big deal.

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.

Yeah, most people say that. Except the people who restore old arcade games and want a CRT instead of an LCD. You are not one of those people.

Cathode ray tubes have been replaced in most of their applications.

Steerable electron beams are still handy - and if fact irreplaceable - in things like electron microscopes, electron beam microfabricators and electron beam welders.

You can - in theory - write finer lines with ion beams - the shorter matter wavelength and the more compact charge help - but electron sources have a lot more development behind them than ion sources.

--
Bill Sloman, Sydney

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.

Steve Wilson wrote in news:XnsAA57296B863Eidtokenpost@69.16.179.22:

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...

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.

I don't undersstand what you are talking about. Display both signals, trigger on one. The one you trigger on will remain stationary. The other will drift. Depending on the quality of the signals, it may take hours or days to show much drift. The signals can be sine waves, square waves, pulses, or any combination. You can't do that with Lissajous.

Not many people make analog audio amplifiers these days.

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

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Design 
Website: https://www.seventransistorlabs.com/

That, and sputtering -- analogous to the difference between a blast of compressed air or a sandblaster!

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Design 
Website: https://www.seventransistorlabs.com/

Audio amplifier tests are performed with analog signals. At a few seconds per unit, not many people were EVER involved in testing those audio products.

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

On a sunny day (Tue, 21 May 2019 18:51:36 -0500) it happened "Tim Williams" wrote in :

As to latency, OLEDs are getting cheaper (about 1000$ for 55 inch IIRC), but will suffer some burn-in for gaming. I almost bought one last week... Picture is stunning.

On a sunny day (Tue, 21 May 2019 23:27:25 -0700 (PDT)) it happened whit3rd wrote in :

Coool, but if you use Linux, install xine, run xine audio_file.wav then bring up the menu with a right mouse click select audio - > visualizations -> goom then you get this display in color, dynamicaly changing in all sort of patterns:

You can also select scope or FFT.

On a sunny day (Tue, 21 May 2019 21:56:46 -0700 (PDT)) it happened whit3rd wrote in :

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...

On a sunny day (Wed, 22 May 2019 11:39:32 +1000) it happened Sylvia Else wrote in :

Yes, the Trio 10 MHz dual channel I bought in 1979 still works and is used as my main scope.

For RF I use my analyzer that is basiclaly an USB DVB-T stick and some software I wrote.

GHz no problem, just downconvert:

those are received SSB signals at about 10.4 GHz downconverted to about 740 MHz...

It is the player, not the instrument.

And I have to stress again and again, you can test a 9V battery with your tongue ! ;-)

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

NT