Electronics > Projects, Designs, and Technical Stuff
Electrostatic vidicons?
Dave92F1:
I want to play around with an analog TV system using non-raster scanning - I want to try spiral scanning, etc., to see what that looks like.
My idea is to have a microcontroller drive the X/Y deflection of a vidicon and also of a (black-and-white) CRT for display. (Or, use an oscilloscope for display).
Would an electrostatically-deflected vidicon be better for this than a magnetically-deflected one? The only electrostatic vidicons I can find on eBay are Soviet LI-441 and LI-475 types.
One vendor ( https://www.ebay.com/itm/Russia-USSR-Vidicon-Vacuum-Tube-LI441-with-deflection-system-OS-5-MilitaryCamera/162951316269 ) is selling one "with deflection system", which confuses me because I thought electrostatic vidicons did all the deflection with voltages at the tube pins (no yoke or anything external to the tube). Am I confused?
I don't know much about this stuff; am trying to learn. Any thoughts from people who know more would be helpful!
jopapeca:
Hi
If you look closer you could see the cable that connects to the deflection could, the outer metallic case are the deflection coils.
I had use those in the past in rx imaging.
Paulo
Enviado do meu SM-G935F através do Tapatalk
chris_leyson:
THOMSON-CSF manufactured a few electrostatic deflection vidicons https://frank.pocnet.net/other/ThomsonCSF/ThomsonCSF_Special-Vidicons_1971.pdf
james_s:
You'll probably have to go with electrostatic if you want to do something like a spiral scan, conventional vidicons use a deflection yoke designed for TV scan frequencies, the horizontal is wound for a much higher frequency than the vertical.
CatalinaWOW:
This is really spoilsporting, but if you are interested in the image artifacts from various scan mechanisms you could just simulate it. Do it all on your PC. Might not be able to generate video frame rates, but you could generate however many frames you want and then play back at full rate. I've seen this done with a number of systems. Some back when it was a real technical challenge, but computer hardware and software has really come a long way.
If you are interested in the artifacts from the processing train you can still do it in simulation, but it is much harder to do, and nearly impossible to know if it is "right". But that isn't totally different from building an analog setup. You can't really know how much of the artifacts are intrinsic to the scan method and processing and how much is due to your specific implementation. I have run into a couple of cases of folks building something to establish feasibility, deciding it isn't feasible, and then finding later they had botched something in the build (or to be more fair, in many cases missed the simple and clever technique that eliminated a huge part of the problems.).
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