Re: Can anybody explain Progressive-PAL please?

In article <4314dbaa$0$1309$ed2619ec@xxxxxxxxxxxxxxxxxxxxxxxxxx>,
Martin Underwood <a@b> wrote:
> "charles" <charles@xxxxxxxxxxxxxxxxxxxxxxx> wrote in message
> news:4da2bb1437charles@xxxxxxxxxxxxxxxxxxxxxxxxxx
> > In article <4314c87a$0$97106$ed2619ec@xxxxxxxxxxxxxxxxxxxxxxxxxx>,
> > Martin Underwood <a@b> wrote:
> >> "Eric Putt" <putte@xxxxxxxxxxxxx> wrote in message
> >
> >> As a matter of interest, does SECAM suffer any artifacts from colour
> >> and luma information overlapping in same the way that PAL and NTSC
> >> suffer cross-colour?
> >
> > probably not - but its years since I worked with Secam. The subcarrier
> > being FM should avoid cross-colour problems. Secam did have another
> > problem
> > in that the output of the colour part was at a fixed level while link
> > fading
> > could change the luminance component; the result was varying colour
> > saturation. Mind you a decent agc circuit should stop that.

> Ah. I'd forgotten that SECAM's colour info was FMed rather than DSB-AMed
> onto the subcarrier. Does SECAM use the same subcarrier as PAL - 4.43 MHz?
No, there are two different sub-carriers, on alternate lines. They're
around 4MHz, but I can't remember what they are.

> How come SECAM can accomodate FM whereas PAL and NTSC can't?

PAL or NTSC could have done, they just weren't made that way. ISTR that the
mono compatability was worse with an FM carrier.

--
>From KT24 - in "leafy" Surrey

Using a RISC OS5 computer
.

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