RE: Questions about pal clocks

From: Marko Mäkelä (
Date: 2001-11-22 15:41:33

On Thu, 22 Nov 2001, Christopher Phillips wrote:

> hmm.. except PAL of course will try to fix this, as it looks like
> drift, which will be happening in opposite directions on alternate
> scan lines.  IIRC, and of course you will probably get no colour at
> all anyway.

I have the experience that PAL decoders (i.e. colour TV sets and monitors)  
are very picky about the colour subcarrier frequency.  Turning the
frequency adjustment knob by just a fraction of a degree can make the
colours totally disappear.  I don't have so much experience in NTSC.  My
NTSC VIC-20 board has a very flaky clock circuit; the picture waves
horizontally, and the computer crashes often when it is cold.  Therefore I
seldom get colours from that board even via a real NTSC decoder.

> In case you hadn't guessed, IANAVideoEngineer :)

Me neither.

Another thing you can try for a rainbow effect is playing with a magnet.
On a black-and-white display, the effect is different: there the magnet
just "stretches" the picture but obviously does not distort colours.  But
beware, the magnet can cause permanent damage.  I never tried it with a
colour monitor.


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