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. -- To the Lords of *Mail to jj@alice.att.com or alice!jj Convention *HASA, Atheist Curmudgeon Division 'Twas Claverhouse *Copyright alice!jj 1989, all rights reserved, except Spoke *transmission by USENET and like free facilities granted.