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Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions.

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Old 22nd Jul 2008, 8:17 pm   #1
Kat Manton
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Default Blanking/Sync - 2V or 4V?

Hi,

A question before I inadvertently blow something up...

I have a Link 102 vidicon camera and CCU, which requires syncs and blanking.

I also have a Pye SPG, which generates said signals. This is currently set up to provide 4V signals but can be adjusted to 2V by moving internal links.

I can't find much information about the camera and don't yet know if it works. Before I connect it all up, I'm wondering whether it's likely to require 2V or 4V signals.

What was commonly used in the UK? The camera is British made and was probably last used at Anglia Television (a long time ago...)

TIA, Kat
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Old 22nd Jul 2008, 10:06 pm   #2
ppppenguin
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Default Re: Blanking/Sync - 2V or 4V?

UK standard is 2V syncs. US standard is 4V syncs. Most equipment really couldn't care less. If all I've had is 2V syncs and the equipment really wanted 4V syncs I've been known to omit the 75R termination
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Old 22nd Jul 2008, 10:11 pm   #3
Kat Manton
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Default Re: Blanking/Sync - 2V or 4V?

Thanks Jeffrey...

...and now you've mentioned termination I'd better check whether the CCU has internal termination or not...
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Old 26th Jul 2008, 10:51 am   #4
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Default Re: Blanking/Sync - 2V or 4V?

I looked at the spec for the Link 103, which is similar technology, and it says "0.7 volt to 6 volts neg going, bridging". So as jeffrey says, it really doen,t care. "Bridging" means that the sync signal loops thro the in/out connectors and the amplifier is high impedance. In an ideal correct world the unused outlet socket should be fitted with a 75 ohm teminating plug. If perchance there is only one connector it is probably internally terminated.

regards beamcurrent
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Old 26th Jul 2008, 4:19 pm   #5
Kat Manton
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Default Re: Blanking/Sync - 2V or 4V?

Hi,

Thanks for the info. With a range of 0.7V - 6V, it's certainly not fussy. It's useful to know that the CCU should work without me wondering about signal level compatibility, so if it doesn't work I can be fairly sure I'm looking for faults.

I've dug the CCU out, it has one connector only for each signal and a quick check (meter and tracing the wiring back to the PCB) shows they're unterminated. For now I'll tack a couple of 75R resistors in there, I'm still very short of 'UHF' T-pieces and cables.

Thanks folks, the camera will doubtless appear in here when I start work on it

Cheers, Kat
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Old 26th Sep 2008, 3:52 pm   #6
Kat Manton
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Default Re: Blanking/Sync - 2V or 4V?

Hi,

An update to this, I've linked the SPG outputs for 2V. To my mind, this offers a little protection for the drivers as there's now an attenuator in circuit. If I accidentally short an output while playing with lashed-up experimental circuitry I shouldn't fry anything.

The CCU seems fine with this signal level; I'm now getting something resembling a video signal out of the camera (which is extremely poorly but that's a subject for a new thread.)

Thanks for the help; this 'end' of television is all new to me but is turning out to be at least as much fun as the other end

Cheers, Kat
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