Zig-zag artifacts on PAL image

What is the reason of these artifacts on propeller generated PAL image? The zigzag lines move up the screen slowly. Not the moire - that is because of camera close to TV screen - but between color bars
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Some LCD monitors etc will try to bring back this SCH and by doing so will cause the chroma to shift along in timing, a bit, then when a whole cycle (235nS) has been used up it will reset and start again. This gives a sawtooth look to the colour edges.
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Why did I think a new, more challenging, job was a good idea ??
Post Edited (Toby Seckshund) : 8/1/2010 9:11:12 AM GMT