Re: vic-ii pal colors

From: Istvan Hegedus <hegedusishe_at_gmail.com>
Date: Mon, 8 Jun 2020 11:23:51 +0200
Message-ID: <CAJG-dDSx79Qo5J-Fsjm6i9qRFSLh2QGqRJM-PC=CTYGQp6y5kQ_at_mail.gmail.com>
Hi,
I am currently investigating the TED analog signals which might be close to
the C64. How do you turn off a comb filter? Is this filter in the RF
modulator?
As I can see TED uses the same saturation for all hues. Even the burst
signal amplitude is the same as the actual color signal. I believe they
made it quite simple.
Btw does anyone know whether the NTSC color phases in the 264 system
specification are reliable? I don't have NTSC monitor/motherboard to test
it.

Thanks
Istvan


On Sun, Jun 7, 2020 at 4:52 PM Michiel Boland <michiel_at_boland.org> wrote:

> Hi. I noticed that if you capture analog C64 video with the comb filter
> turned
> off there is quite a difference in color saturation and/or hue between
> even and
> odd lines.
>
> I thought that the colors were generated by adding a weighted sum of sine
> and
> cosine signals, but inverting one of the inputs (which is done in odd
> lines in
> PAL systems) should not have any effect of the overall amplitute, unless I
> am
> very much mistaken.
>
> Has any more research been done into this?
>
> Cheers
> Michiel
>
> FWIW I have taken some measurements here:
> http://www.michiel.boland.org/c64_colors.html
>
>
Received on 2020-06-08 12:00:02

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