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Path: utzoo!linus!philabs!cmcl2!rna!cubsvax!peters
From: peters@cubsvax.UUCP (Peter S. Shenkin)
Newsgroups: net.audio
Subject: Re: Digital Remastering
Message-ID: <337@cubsvax.UUCP>
Date: Thu, 30-May-85 09:41:43 EDT
Article-I.D.: cubsvax.337
Posted: Thu May 30 09:41:43 1985
Date-Received: Sat, 1-Jun-85 10:53:59 EDT
References: <356@lcuxc.UUCP> <>
Reply-To: peters@cubsvax.UUCP (Peter S. Shenkin)
Organization: Columbia Univ Biology, New York City
Lines: 29
Summary: 

In article <> thomas@utah-gr.UUCP (Spencer W. Thomas) writes:
>
>One advantage of "digital remastering" comes in if you are going to make
>MANY copies of the new master.  Each time you copy (play) an analog
>master, you lose a little fidelity.  Each time you copy (play) a digital
>master you lose nothing.  
>
One thing I've always wondered, and even though it's not quite within the
provenance of net.audio, now seems a good time to ask it.  When you copy
(play) a digital master, isn't there a finite proability of mis-copying a
bit?  I mean, even if parity bits are used, there's a finite probability
of mis-copying an *even* number of bits, and no matter how many double-
checks one cares to make, there's always a *finite*, though small, prob-
ability of a miscopy getting through all of them, it would seem.  Thus, isn't
it incorrect to state that "you lose nothing"?  I mean, think of how many
bits there must be on a CD.  (OK, how many?  I'm sure many of you know!)
Even with a very low error rate there must be a few that have been mis-
copied... and if you know what the error rate is, and also a ballpark figure
for what percentage of bits would have to be wrong for an audible effect,
one could calculate how many generations of copies would be necessary to
audibly degrade the signal -- I agree it's going to be a big number!
(Assume random distribution of wrong bits....)

Thus, the *nature* of signal degradation through repeated copying would 
seem to be the same with analog and digital encoding... it's just that 
digital *technology* allows one to keep the error rate down much more
*cheaply*.  Is this a correct understanding?  (Obviously, I'm not an ee....)

Peter S. Shenkin	philabs!cubsvax!peters		peters@cubsvax.UUCP