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From: nrh@lzwi.UUCP (N.R.HASLOCK)
Newsgroups: net.graphics
Subject: Re: RGB to composite?
Message-ID: <339@lzwi.UUCP>
Date: Fri, 4-Oct-85 16:53:30 EDT
Article-I.D.: lzwi.339
Posted: Fri Oct  4 16:53:30 1985
Date-Received: Sun, 6-Oct-85 04:41:31 EDT
References: <10500004@uicsl> <338@gcc-bill.ARPA>
Organization: AT&T Information Systems, Lincroft
Lines: 28
Summary: atari technique

In article <10500004@uicsl> hr@uicsl.UUCP writes:
>A friend asked me if I would ask you:
>	Is there a simple way, say a chip, to convert RGB(I) signals
>	to composite video?
>I doubt the application requires extreme precision. I think it may have
>something to do with a Commodore 128.
>						harold ravlin
>					{ihnp4,pur-ee}!uiucdcs!uicsl!hr

This is taken from my copy of the Atari 800 logic.

comp video is sync + chroma + luminance

luminance ---> op amp --------+----+-----> comp video --> rf modulator
                              |    |
sync ---> op amp --> diode -->+    |
                                   |
color---> op amp --> 100pf -> 1k --+
-- 
--
{ihnp4|vax135|allegra}!lznv!nrh
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