piclist 2000\11\29\033808a >
Thread: Video: Color to B/W conversion
face BY : David VanHorn email (remove spam text)

At 02:02 AM 11/29/00 -0500, you wrote:
>Hi Dave,
>Thanks,but I want to ask a further question because I don't totally
>understand how that's true. If I'm looking at an NTSC color composite video
>signal, isn't the subcarrier just added in to the signal? If so, why
>wouldn't a comparator pick it up (i.e., if the B/W video level is -0.25,
>and the subcarrier instantaneous voltage is 0.5 V, then why doesn't the
>comparator act like the level is 0.25 V ?)

The subcarrier is phase modulated, and low amplitude.
If this were a problem, you'd see it in a B/W tv, as distortion of the

Also, the speed of your comparator is critical here.
You could lowpass your video, but this will get you phase distortion.

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See also: www.piclist.com/techref/displays.htm?key=video
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Subject (change) Video: Color to B/W conversion

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