Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!apple!oliveb!tymix!antares!doctor!jms
From: jms@doctor.Tymnet.COM (Joe Smith)
Newsgroups: comp.sys.amiga
Subject: Re: Color composite on A500, and other questions.
Summary: Don't expect 80 column text
Keywords: composite color video vs 640 resolution
Message-ID: <215@doctor.Tymnet.COM>
Date: 19 May 89 00:04:28 GMT
References: <413@aucis.UUCP> <105356@sun.Eng.Sun.COM>
Reply-To: jms@doctor.Tymnet.COM (Joe Smith)
Organization: McDonnell Douglas Field Service Co, San Jose CA
Lines: 31

In article <105356@sun.Eng.Sun.COM> cmcmanis@sun.UUCP (Chuck McManis) writes:
>In article <413@aucis.UUCP> (Andrew Gillham) writes:
>> I just managed to scrape together enough money for the A500 and would 
>> like to run it in color on my tv.. Any suggestions?  Thanks..
>
>I can appreciate this. Can you stand it in monochrome for a month or
>two while you figure out a way to come up with $50 ? I'd guess it would
>be easier to mow 10 lawns for $5 apiece than it would to build this
>thing on your own, but then again I don't know your situation.

I had one friend complain after spending mucho bucks for a high quality
genlock, that 80 column text looked lousy on the color composite output.  He
started flaming about "bad design" and such, and it took a bit of explaining
to calm him down.

A genlock (or RGB converter) has to conform to NTSC standards, which
includes encoding the color (chroma) information on a 3.58 megaHertz 
subcarrier.  When the TV tries to separate the composite signal into
chroma and luma (b&w) signals, the portions of the luma signal at 3.58
and 7.16 MHz get filtered out.  Since 80-column text has a lot of signal
energy at 7.16 MHz, the text gets blurred.  And if you have to go through
an RF modulator so your TV picks up the signal on Channel 3 or 4, the
text gets even blurrier.

In summary, don't expect 80 column text to look good on your color TV.
You can read it, but with some difficulty.
-- 
Joe Smith (408)922-6220 | SMTP: JMS@F74.TYMNET.COM or jms@tymix.tymnet.com
McDonnell Douglas FSCO  | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jms
PO Box 49019, MS-D21    | PDP-10 support: My car's license plate is "POPJ P,"
San Jose, CA 95161-9019 | narrator.device: "I didn't say that, my Amiga did!"