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Article #1934Re: 180 deg phase shift
From: John Whitmore
Date: Wed, 15 May 1991 05:50
Date: Wed, 15 May 1991 05:50
25 lines
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1653 bytes
In article <625@fudd.dataco.UUCP> mcphail@taarna.UUCP (Alex McPhail,DC ) writes: > Since any periodic function is always measured against time, >shifting the function's phase is also a time-related operation. > > .... frequency and Fourier components >have nothing to do with phase shifting. I disagree. In discussing networks (or filters), one usually refers to the Bode plot of amplitude and of phase shift plotted against frequency. The normal meaning in the context of filters of the phrase 'phase shift' is the phase part of that representation, and 'constant 180 degree phase shift' is clear and unambiguous. It means amplitude inversion. What earthly use are 'degrees' in describing the phase of something which is not a circular function? And, why do you refer to 'any periodic function' in this discussion? To the best of my recollection, there was never any statement made that the function under discussion was periodic. Phase shifts are well-defined in the absence of periodicity, though easier to measure and display in the case of periodic test waveforms. John Whitmore
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<1991May8.222501.19572@syd.dms.CSIRO.AU> <1991May10.003817.5593@milton.u.washington.edu> <625@fudd.dataco.UUCP>Show Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!cs.uoregon.edu!ns.uoregon.edu!milton!whit From: whit@milton.u.washington.edu (John Whitmore) Newsgroups: comp.dsp,sci.electronics Subject: Re: 180 deg phase shift Message-ID: <1991May15.055011.5823@milton.u.washington.edu> Date: 15 May 91 05:50:11 GMT References: <1991May8.222501.19572@syd.dms.CSIRO.AU> <1991May10.003817.5593@milton.u.washington.edu> <625@fudd.dataco.UUCP> Organization: University of Washington, Seattle Lines: 25