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jim_beacon · 1st Jun 2006, 9:28 pm

A little more progress.....

I have taken Kats Mk2 RGB / sync combiner, and redesigned the DC coupled amp stages using video op-amps. I can now set video level, sync level and DC offset (sync tips at 0V or -300mV, or for that matter, anywhere else) independantly. I have also done a little work on the power supply, redesigning it for 9V AC input, giving regulated +5V and -5V rails, though this was purely for personal preference.

The design still uses the basic XOR sync combiner, but as this works reasonably well, I'm going to leave it for now.

The new design still needs some tweaking, but initial results are good, and it should have more than sufficient bandwidth to handle standards up to 819 lines (the op-amp I used - AD828 - is quoted as flat to 40MHz, with a gain / bandwidth product of 140MHz).

I'll bring both versions along on Sunday.

Jim.

1st Jun 2006, 9:28 pm	#81
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: PC as a standard convertor A little more progress..... I have taken Kats Mk2 RGB / sync combiner, and redesigned the DC coupled amp stages using video op-amps. I can now set video level, sync level and DC offset (sync tips at 0V or -300mV, or for that matter, anywhere else) independantly. I have also done a little work on the power supply, redesigning it for 9V AC input, giving regulated +5V and -5V rails, though this was purely for personal preference. The design still uses the basic XOR sync combiner, but as this works reasonably well, I'm going to leave it for now. The new design still needs some tweaking, but initial results are good, and it should have more than sufficient bandwidth to handle standards up to 819 lines (the op-amp I used - AD828 - is quoted as flat to 40MHz, with a gain / bandwidth product of 140MHz). I'll bring both versions along on Sunday. Jim.