Newsgroups: comp.sys.mac.hardware
Path: utzoo!censor!geac!alias!tom
From: tom@alias.UUCP (Tom Burns)
Subject: Re: Does the 8.24 card do NTSC video?
Message-ID: <tom.659129708@warp2>
Sender: news@alias.uucp (USENET News)
Organization: Alias Research, Inc. Toronto ON Canada
References: <4763@dogie.macc.wisc.edu>
Date: 20 Nov 90 19:35:08 GMT

In <4763@dogie.macc.wisc.edu>yahnke@vms.macc.wisc.edu(Ross Yahnke, MACC) writes:

>RS-343 standard. Supports RS-170 timing standard for interlaced
[...]
>Does this mean the card can produce a NTSC signal? Could I just
>plug my VCR into it and record the Mac video display?

Nope, sorry.  RS-343 is a 60Hz non-interlaced analog video signal
running anywhere from ~30KHz to ~60KHz (horizontal scan rate).

RS-170 is an interlaced 30Hz video signal running at 15.75 KHz. So if
you have three 'monochrome' RS-170 signals R, G, and B, they can be
encoded into an NTSC signal (RS-170A - the 'A' is the difference). An
encoder will cost you anywhere from a few hundred to tens of thousand $$.

Typically Mac cards which support RS-170 signals say somewhere that you can
take just the green channel and record it on your VCR as a B&W video signal.
This works about as well as you'd expect.

--
Tom Burns, aka "The Video Guy" at:  | "Ebben ne'andro lontana" - La Wally
Alias Research Inc. (416) 362-9181  |  Fax: (416) 362-0630	
110 Richmond St E, Toronto M5C 1P1  |  DOMAIN: tom%alias@csri.toronto.edu
