Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!rutgers!dptg!ulysses!andante!alice!jj
From: jj@alice.UUCP (alice!jj)
Newsgroups: comp.dsp
Subject: Re: sound data compression
Message-ID: <9966@alice.UUCP>
Date: 25 Sep 89 14:45:38 GMT
References: <6028@jpl-devvax.JPL.NASA.GOV> <89255.105143P85025@BARILVM.BITNET>  <7767@microsoft.UUCP> <89264.171306P85025@BARILVM.BITNET> <8909@batcomputer.tn.cornell.edu> <7814@microsoft.UUCP> <1900@cunixc.cc.columbia.edu>
Reply-To: jj@alice.UUCP (alice!jj)
Organization: ATT-BL, Murray Hill, Signal Processing Research Department
Lines: 21

In article <1900@cunixc.cc.columbia.edu> brad@woof.columbia.edu (Brad Garton) writes:
>In article <7814@microsoft.UUCP> brianw@microsoft.UUCP (Brian Willoughby) writes:
>>Just by storing the *difference* between
>
>I've wondered about this before -- is this the technique known as
>"delta modulation"?  I seem to recall some DACs made by dbx on the
>market some years ago that employed such a scheme.  I gather one
>of the problems was that errors would start being compounded.
The scheme is called "Differential PCM", and delta modulation
is a sub-set of the basic technique.

Jayant and Noll, "Digital Coding of Waveforms", has a rather complete,
although tough-mathwise, discussion of DPCM, and of various variants
of DPCM, including Delta Modulation.  Ray Steele has an older
book out on Delta Modulation alone, I don't remember the title
off the top of my head.
-- 
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