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Posted by Roderick Stewart on 10/12/06 12:15
On Wed, 11 Oct 2006 13:49:37 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:
>>Strictly speaking an NTSC decoder should have it's demodulator phases
>>aligned with the I and Q axes, and the resultant signals matrixed to
>>produce R-Y and B-Y, but it is quite common for the phases to be
>>aligned with the R-Y and B-Y axes. You don't get the advantage of
>>extra chroma bandwidth in one of the signals (can't remember which
>>one), but it works and most people can't tell the difference.
>>
>>Rod.
>
>OK, yes, IIRC the Sony actually had 3 demodulators, one for R, one for G,
>and one for B ;-) (KV2000 chassis?)
>I remember looking at that diagram for a long time wondering??????
>No matrix!!
>And it could do PAL, came with hue control to rotate the phase...
>(Was looking for a KV2000 diagram to look it up, not for free on the net it
>seems).
I don't recognise the chassis number, but I do remember the first Sony
PAL sets had some unconventional decoding circuitry to avoid
infringing the Telefunken patents. They had to derive the half line
frequency switching signal of course, but only used it to switch the
decoding phase of one of the demodulators and made no use of it for
any phase cancellation of chroma errors, presumably on the premise
that phase cancellation is the thing that made PAL distinct from NTSC.
I wonder if this point was ever actually argued in court? A case like
that could have run for years, even if any lawyers could be found that
could understand the technology. You'd think it would be cheaper just
to pay the royalties like everybody else.
Rod.
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