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Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!petrus!karn
From: karn@petrus.UUCP
Newsgroups: net.video
Subject: Re: unrecordable video??
Message-ID: <274@petrus.UUCP>
Date: Sun, 3-Feb-85 18:32:27 EST
Article-I.D.: petrus.274
Posted: Sun Feb  3 18:32:27 1985
Date-Received: Mon, 4-Feb-85 05:29:41 EST
References: <9700002@hp-pcd.UUCP>
Organization: Bell Communications Research, Inc
Lines: 14

> Anyone have any info on how this can be done?
In the past, this has been done by modifying the sync pulses such
that they're still good enough for a TV, but not good enough for the
servos in a VCR. This is the "Copyguard" technique.  Such a system
can be easily defeated with a common device in the TV station called
a "processing amplifier" or "proc amp" for short. It regenerates the
sync signals back to their standard form.  I suspect that the scheme
described here will be similar.

Attempting to make signals displayable on TVs but not recordable seems
doomed to failure. Even without proc amps, one could always record
after a fashion by simply pointing a camera at the screen!

Phil