OT - CRT's

With 3 guns it's almost a triple somethingode. The common anode is a bit of an issue :) So maybe a logic gate.

NT

Reply to
tabbypurr
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I love my Tek 7704A and the inserts for it but the TDS220 series was horrid.

When I bought a DSO about 10 years ago I chose GW-Instek because the twice as expensive Tek had worse noise and way less sample memory which made it useless for pulse-echo work.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

My high school science project was "The Cathode-Ray Tube as an Active Circuit Element." I made it to the National Science Fair in Baltimore and we got a tour of the White House. I stepped into the Oval Office. We were scheduled to meet LBJ but he got called away at the last minute.

I palled around with Amory Lovins in Baltimore, who is now some sort of environmentalist guru.

Somebody made a CRT with an etched metal mask that was a ROM character generator.

There was also a tube with an electrostatically deflected sheet beam and two anodes, used as a balanced modulator.

And a dark trace CRT.

And radial deflection tubes used in radio altimeters.

And a companding 8-bit grey-code CRT ADC, used in the first PCM telephone systems.

There were gas-filled CRTs where you could see the electron beam.

--
John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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Reply to
John Larkin

The trigger in that series is unsurpassed. What is absolutely not cool is the delayed-trigger clutch. It is an undersized piece of fairly brittle plastic behind the front panel and one sunny day it happened at a client ... crack. To my surprise there was a guy in Greece who made and sold a nearly complete set of new front panel plastic parts. Installing all that took almost an hour but then the client had a scope good as new. While waiting for the stuff I could coax it into delayed trigger by operating the slide switch behind the panel with a bent wire hook.

Those sampling scope mainframes are tempting but I just don't have the space. Since I am gradually retiring it would also be hard to justify the expense in front of SWMBO, especially now that I might need to buy a new road bike.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

The 7360, possibly still the world's strongest mixer. I have a couple in the drawer that I've been meaning to use for something. Maybe I'll use a krytron and make an exploding-wire remote control doorbell. ;)

Cheers

Phil Hobbs

Reply to
pcdhobbs

Yup, I have two of the 2-m ones too, and as you say, they're dead useful. I even found one each of the SD-46 and SD-48 20 and 30 GHz O-E converters for fairly cheap. Ebay saved searches and patience, man. ;)

Cheers

Phil Hobbs

Reply to
pcdhobbs

** That comment is massively ambiguous, same as a lot of Hobbs OTT comments.

Any decent scope has very fine trace, revealing waveform detail that makes any LCD screen scope look primitive.

Picture tubes use a raster system with limited vertical resolution, again visible waveform detail is not in the same league as a CRT scope. If the image is colour, convergence is never perfects.

The ONLY sense in which Mr Hobbs is correct is the electrostatic focus of the electron beam may not be perfect at the edges of the CRT face. A trivial concern.

.... Phil

Reply to
Phil Allison

They did--it could do 1 ps/div, for only $100k. I had a purchase req for on e turned down in late 2008 when DARPA canned the program that was going to fund my continuing tunnel junction optical communication project. (The prog ram manager then tried to fund just us, but couldn't make it happen.)

Cheers

Phil Hobbs

Reply to
pcdhobbs

Am 25.05.19 um 00:06 schrieb snipped-for-privacy@gmail.com:

Yes, made by RCA. I have a few, too. There is one in the SSB balance modulator of my Yeasu FT505 shortwave transceiver. It would have been much better to use it in the 2nd mixer.

I bought that in a previous life, as it seems now. Maybe it still works, have not checked it for 30 years =:O

regards, Gerhard

Reply to
Gerhard Hoffmann

us of the >electron beam may not be perfect at the edges of the CRT face. A trivial concern.

Which is why Mr Allison probably thinks that SEMs use electrostatic focusin g. ;)

Cheers

Phil Hobbs

Reply to
pcdhobbs

Am 24.05.19 um 23:55 schrieb John Larkin:

And a transient recorder by Tek based on a tube, 200 MHz IIRC. Where usually is the phosphor, there were capacitors that collected electrons from the beam and they could be read out.

They demo-ed us that thing, but we ended up with the newest

20 MSPS 8 bit flash ADC from TRW. A chip the size of a fingernail.

regards, Gerhard

Reply to
Gerhard Hoffmann

There were scan-conversion tubes, two CRTs face-to-face, one writing and one raster scanning.

The Tek 7 GHz scan converter tube was French, and you can still buy one.

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Nice company name and logo.

--
John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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Reply to
John Larkin

Phil Allison wrote in news: snipped-for-privacy@googlegroups.com:

I think that you 'looked' years ago and 'dismissed'.

They are far better now at displaying what BOTH devices have no problem capturing.

Reply to
DecadentLinuxUserNumeroUno

** FYI I have a Rigol DSO.

** Irrelevant bullshit.

Go f*ck yourself.

.... Phil

Reply to
Phil Allison

No, that's only for short ones with big screens. An oscilloscope that uses a long tube, small screen, is of the electric field deflection type.

Reply to
whit3rd

so how do you make that behave like a PM altenator? I would expect that to behave much more like a voltage source, are you putting transformers on the output or something?

--
  When I tried casting out nines I made a hash of it.
Reply to
Jasen Betts

Phase is conserved when mixing down, so mixing against a stable oscillator will give lower frequency data with the same percent jitter; the analog scope will display it fine.

A truly flexible X/Y display that works in realtime is hard to replace with digital.

Reply to
whit3rd

On a sunny day (Fri, 24 May 2019 18:50:34 -0700 (PDT)) it happened Phil Allison wrote in :

Not exactly Old scope tubes used electrostatic focusing, but old TV CRTs (BW) used magnetic focusing either with permanent movable magnets or electro magnets,

Let's go back in time to BW TV, and look at the MW31-17 CRT for example:

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Pic the years...

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Download:

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On page 2, it says in English Focusing magnetic the number of ampere-turns necessary for focusing at Va2 = 7000 V is 580-720 at a distance of about 36 from the coil center to the screen ... etc

Nice datasheet. I have used similar tubes, even tried winding my own deflection coils back then.

And then there was the magnetic ion-trap

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also present in old BW picture tubes
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There is more, but 'its early.

Reply to
Jan Panteltje

On a sunny day (Fri, 24 May 2019 14:55:56 -0700) it happened John Larkin wrote in :

You should have stayed there!

;-)

Reply to
Jan Panteltje

AIUI early CRTs used the redisual gas for focussing.

You could say the CRT was an active circuit element in early colour sets too, IIRC there were 2 different signals applied to cathodes & grids, using the tube itself to compute the correct colour outputs.

NT

Reply to
tabbypurr

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