Xref: utzoo comp.dsp:1623 sci.electronics:19972 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!sdd.hp.com!think.com!yale!cs.yale.edu!rt4-gw.cs.yale.edu!jim From: jim@fuji.eng.Yale.edu (James J. Szinger) Newsgroups: comp.dsp,sci.electronics Subject: Re: 180 deg phase shift Message-ID: Date: 7 May 91 19:10:24 GMT References: <1991May5.233533.18783@ux1.cso.uiuc.edu> Sender: news@cs.yale.edu (Usenet News) Organization: Yale Univerity, Intelligent Sensors Lab, Elect. Eng. Lines: 28 In-Reply-To: frerichs@adsl's message of 5 May 91 23: 35:33 GMT Nntp-Posting-Host: fuji.eng.yale.edu In article <1991May5.233533.18783@ux1.cso.uiuc.edu> frerichs@adsl (dfRERICHS) writes: Does anyone know the algorithm that would take a stream of sampled sound ,shift it 180 deg in phase and spit it back out again? ie sound -> a/d -> dsp to shift phase -> d/a -> sound (it would seem from the nature of the problem that a simplistic analog circuit to do this might be possible... some sort of RC net... if anyone know if this is possible, PLEASE make it known.) Thanks djf I think what you are looking for is the Hilbert Transform. A Hilbert Xform shifts the phase of the signal by 90 degrees. Just cascade two of them together for a total of 180 degrees. There might be an easier way but I can't quite think of it. Jim -- James J. Szinger Becton Center jim@fuji.eng.yale.edu 15 Prospect Street Intelligent Sensors Lab. Box 2157 Yale Station Electrical Engineering New Haven, Connecticut 06520 Yale University U.S.A.