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From: philip@axis.fr (Philip Peake)
Newsgroups: sci.electronics
Subject: Re: NTSC-PAL (in)compatibility
Message-ID: <566@axis.fr>
Date: 20 Jun 89 11:08:58 GMT
References: <124@nisca.ircc.ohio-state.edu>
Organization: Axis International, Paris
Lines: 32

> I would like some adivce/references about compatibility/incompatibility
> between the NTSC and PAL color TV systems. I have several questions like:
> Are b/w receivers built for the NTSC and PAL markets compatible? B/w
> signals recorded on VHS tapes? Are there any add-on products that let you
> see VHS tapes recorded with NTSC signals on PAL systems?
> Are VHS VCR's compatible, or do they have special components directed
> toward the interpretation of NTSC or PAL signals?

I can't say too much about NTSC/PAL, but my experience of PAL/SECAM
indicates that although the basic VHS system is the same, the encoding of
the info on the tape is not compatible between the two.

The main difference between PAL and SECAM is how the colour info is coded
(the sub-carrier frequencies are different, and the means of indicating
the current phase of the colour info is different) - the line frequencey
is the same though (not true for NTSC).

On moving from England to France, I tried using my english (PAL) vcr
to play SCAM tapes, and lent some of my PAL tapes to people with SECAM
vcrs. The result was the same in both directions - good B&W picture
and sound, but absolutley no colour.

I would be interested if anyone could explain why the difference in
coding between the two systems - I would have just put the colour info
directly onto the tape ona parallel track - this would give compatability
between the two systems.

As it is, I bought a new vcr PAL/SECAM model, which solves the
problem - maybe this is why the coding is different - to make bigger
profits from selling dual standard machines, where one would do ?

Philip