Re: Difference in luma-chroma delay of C64/C128 compared to standard S-video

Den Mon, 4 Sep 2017 23:55:36 +0200 skrev silverdr@wfmh.org.pl:
> 
> > On 2017-09-04, at 18:49, smf <smf@null.net> wrote:
> > 
> > On 04/09/2017 17:29, silverdr@wfmh.org.pl wrote:
> >> I am not sure if we talk the same subject now. What I am trying to
> >> say is that there is no perceptible/measurable difference in Y/C
> >> timing between the separate and combined (composite) signals in a
> >> reference output. I can do the same with a 64, although - the same
> >> as Levente - I expect that whatever the modulator changes with its
> >> rather simplistic circuit is still negligible.
> >> 
> > Sure. Timing between composite, chrominance & luminance on an 8 pin
> > would settle the debate.
> 
> This is on a 250466, don't know what exactly (what circuit) sits in
> the modulator there. While obviously the signal is far less clean
> from a 64 than from the generator, the results seem to be:
> 
> - C alone and C on the composite seem to be almost exactly the
> reversed phase.
> - the "almost" is about plus 17ns for the composite C

Should this be counted as a simple phase inversion (haven't looked into
the schematics of the modulator today) or a delay of about one half
wave? One half wave could probably match the incorrect timing I see on
my CRT.

> - Y alone and Y on the composite seem to be about 23ns apart
> - the "settling"[*] on composite is noticeably longer with some
> ringing
> 
> That makes it about 6ns difference in Y/C luma-chroma time relation
> between the separated and composite.

How does it compare to a reference signal though?


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