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Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions. |
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9th Feb 2006, 9:44 pm | #21 |
Pentode
Join Date: Nov 2003
Location: Chelmsford, Essex, UK.
Posts: 121
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Re: The valve option
Greetings to all.
For the delectation of interested parties, I believe the attached may be the EF50-based circuit referred to by Danny. It is part of a project published by Radio Constructor, this part of the project appearing in the October 1953 issue. The project as a whole was called "The Pattern_Master"; not surprisingly it was a TV pattern generator (405 in those days, naturally).
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Regards David F. Symes |
9th Feb 2006, 11:16 pm | #22 |
Heptode
Join Date: Jul 2003
Location: North Walsham, Norfolk, UK.
Posts: 516
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Re: The valve option
Hi arrr thats the curcuit he gave me but i didnt know where it came from in the first place i must email my friend to get the rest as this could be usefull when i have to build the master sync generator for the flyingspot scanner!. hopefully i can have a play this weekend if she dont catch me that is. ive got lots of chores to do .
But the origanal cercuit was based on a ham project and i altered it a bit to try to get it to act as a modulatorfor video instead of a beacon!. Danny |
25th Mar 2006, 12:14 pm | #23 |
Rest in Peace
Join Date: Apr 2005
Location: Devon
Posts: 850
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Re: The valve option
I know this is going a lot further, but has anyone considered building a valve standards converter without any solid state circuitry? I'm guessing it would be enormous, bigger than the solid state unit Gerry Wells has, but how easily could this be achieved? I have a picture of the optical converter used by the BBC, but I was thinking more along the lines of all electronic, but all valve circuitry. Just a thought.
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25th Mar 2006, 12:24 pm | #24 | |
Retired Dormant Member
Join Date: Dec 2003
Location: North London, UK.
Posts: 6,168
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Re: The valve option
Quote:
As for a digital converter, the amount and speed of the logic would make it extremely difficult with discrete transistors let alone valves. If you threw enough resources at the problem you could probably get an answer, rather like NASA threw resources into the computers for the Apollo missions to achieve results that looked pretty much impossible. |
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25th Mar 2006, 2:07 pm | #25 |
Retired Dormant Member
Join Date: Mar 2003
Location: Bishop's Waltham, Hants, UK.
Posts: 939
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Re: The valve option
We had some valve standards convertsers at work, for turning polar radar displays into raster scan for the addition of secondary radar labels. They used a special converter tube, which was effectively a camera and picture tube in one envelope. The writing beam wrote onto a charged plate, which was then read by a second electron beam.
Jim. |
25th Mar 2006, 2:29 pm | #26 | |
Retired Dormant Member
Join Date: Dec 2003
Location: North London, UK.
Posts: 6,168
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Re: The valve option
Quote:
Just a thought, I wonder if the Williams tube (used for memory in some very early computers) could be pressed into service as part of a valve digital converter. This is not a serious thought! |
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25th Mar 2006, 4:27 pm | #27 |
Rest in Peace
Join Date: Apr 2005
Location: Devon
Posts: 850
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Re: The valve option
Going from a purely analogue angle, how easy would it be to build a valve converter which quite simply removed every 3rd line?
Obviously a total valve based converter is possible, but I do have to wonder at the size of it. |
25th Mar 2006, 4:41 pm | #28 | |
Retired Dormant Member
Join Date: Dec 2003
Location: North London, UK.
Posts: 6,168
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Re: The valve option
Quote:
BBC engineers didn't even attempt an electronic converter until transistors were capable of operating at video bandwidth and their solution was a pretty massive "state of art" design in the early 1960s. It might have been theoretically possible with valves but the number of valves would have been into 4 figures. The sort of thing you would only attempt with military necessity and budgets. |
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