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From: jj@alice.UUCP
Newsgroups: net.audio
Subject: Re: Noise due to digital errors, error correction, etc
Message-ID: <3847@alice.UUCP>
Date: Sun, 9-Jun-85 21:52:58 EDT
Article-I.D.: alice.3847
Posted: Sun Jun  9 21:52:58 1985
Date-Received: Tue, 11-Jun-85 03:11:34 EDT
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Organization: New Jersey State Farm for the Terminally Bewildered
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Sorry, Dave, that might be the "obvious" reason to you, but
it's not the reason for ECC's at all.  It's the reason for
TIME DIVERSITY (i.e. the cross interleave, but not the
ECC).   

In any case, it's necessary to have both ECC and time diversity.
The "blob" graphically demonstrates the reasons for diversity,
and the fact that the average player does ECC twice a second
on a GOOD disk demonstrates the reason for ECC.  To put it
otherwise, there would be a full scale CLICK every 8 seconds
on the average if there wasn't.  That click, alone, would
render the disc completely impossible.  The blobs would, too,
of course.

There are many papers in ICASSP and IEEE-Com Transactions that
talk about errors in PCM codes of various sorts.  Read one
and you'll see what I mean.
-- 
TEDDY BEARS HAVE LIMITED PATIENCE! THEY DO EVENTUALLY GET HUNGRY!
"Let us remember my cat, Geoffrey, ..."

(ihnp4/allegra)!alice!jj