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From: mlelstv@medusa.informatik.uni-erlangen.de (Michael van Elst )
Newsgroups: comp.sys.amiga,comp.sys.amiga.tech,comp.sys.amiga.hardware
Subject: Re: A3000 Video Chips
Message-ID: <3004@medusa.informatik.uni-erlangen.de>
Date: 16 Jul 90 11:15:40 GMT
References: <4741@munnari.oz.au> <13060@cbmvax.commodore.com> <16713@windy.dsir.govt.nz> <13076@cbmvax.commodore.com> <272@cbmger.UUCP>
Organization: CSD, University of Erlangen, W-Germany
Lines: 15

peterk@cbmger.UUCP (Peter Kittel GERMANY) writes:
>Heaven help! Does that mean that if we in Europe want to do video stuff,
>we still have to build other mother boards with a different crystal?
>1 % difference wouldn't be tolerable!

Yes, 1% difference wouldn't be tolerable. But in Europe we have the
far better PAL system. The color is determined from the phase shift
between the color burst and the modulated color sub carrier.
If both are generated from the same crystal, you can have much higher
tolerances against the PAL specs. Nevertheless, cheap PAL decoders could
fail if they avoid the proper PLL curcuit and just phase shift another
crystal's signal to match the color burst.

Michael van Elst
p554mve@mpirbn.mpifr-bonn.mpg.de