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From: brown@vidiot.UUCP (Vidiot)
Newsgroups: rec.video,sci.electronics
Subject: Re: RGBS -> Y/C
Message-ID: <1883@vidiot.UUCP>
Date: 6 Jun 91 16:48:13 GMT
References: <13965@pasteur.Berkeley.EDU> <1862@vidiot.UUCP> <2829@otc.otca.oz>
Reply-To: brown@vidiot.UUCP (Vidiot)
Organization: Vidiot's Hangout
Lines: 57

In article <2829@otc.otca.oz> siri@otc.research.otca.oz.au (Siri Hewa) writes:
<>
<>|In article <13965@pasteur.Berkeley.EDU> anantha@zabriskie.berkeley.edu (Anantha Chandrakasan) writes:
<><
<>|<Does anyone know of a chip or chips that will take analog RGB and S (sync)
<>|<signals and convert it into Y (with sync encoded) and C signals. I want to
<>|<record the RGBS video signal on a S-VHS recorder.
<>
<>|WARNING: Unless the RGB signal is NTSC compatible with regards to the frame
<>|rates, you will not be able to record the output.  All other RBG frame rates
<>|MUST be sent through a RGB to NTSC converter.  The only RGB that was even
<>|close to NTSC was the IBM CGA standard.  All analog RGB rates that I know of
<>|are not NTSC compatible.
<
<Iam sorry to say, this person don't have any theoratical or practical knowledge
<of the video signal. You can't say that All analogue RGB rates are not NTSC
<compatible, Analogue RGB in video world, ie Broadcast and Domestic is One volt
<p-p, NTSC, is 60 Hz, and 525 lines. Pal is 50 Hz, and 625 lines. And no more
<crap.

Ok, Ok, I should have said computer generated analog RGB output, from such
computers as the Sun Workstation and IBM-PC compatible computers.  Computer
generated RGB for broadcast use will obviously be correct.  While it is true
that the original poster didn't say what his source was, I was assuming that
it was from a personal computer of some sort.

And I do know about video.  The wording just came out wrong.

<Now you can get into Computer domain, with TTL and Linear RGB (Analogue).These
<days computers get there Hi-Res from incresing scan rates.
<For your video NTSC is 15.75 KHZ, and Pal is 16.625 KHZ.

For NTSC it is really 15,734 and PAL is 15,625 Hz.

<But for the computer scan rate can start from 17.75 KHz to 64 KHz and more. And
<from that you can derive the screen resolution. So different resolutions come
<from different scan rates, and this is not the only way of doing things, and
<there are other methods as well.

Yes, I knew that.  That is why I said what I did.

<>|The exception is the Amiga series of computers.  Those were designed for video
<>|work in mind.  So you can purchase all kinds of various boards and external
<>|options for getting NTSC output in composite or S-video.
<>
<>|But the IBM-PC compatible and Sun Workstation RGB outputs are not NTSC rated.
<
<You are right here. But Don't confuse this with normal video signal.

I wasn't trying to confuse it with a "normal" video signal.  What I was trying
to get across, not very well, was the fact that too many people think that
if they can see it on a screen they can record it on their VCR.  That is far
from the case in many situations.
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