Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!spool.mu.edu!uunet!comp.vuw.ac.nz!wnv!grace!srgpmap
From: SRGPMAP@grace.dsir.govt.nz
Newsgroups: comp.dsp
Subject: Re: 180-deg phase-shift -- A study in Usenet tech
Message-ID: <11945@grace.dsir.govt.nz>
Date: 13 Jun 91 16:08:37 GMT
Organization: DSIR, Gracefield, New Zealand
Lines: 6

Here is another theoretical breakthrough. It has been stated that a perfect
reconstruction filter for sampled audio has an infinite impulse response,
due to the infinitely sharp cut-off required at the Nyquist frequency. However,
a finite duration reconstruction filter with an impulse response which is a
half sine pulse (at a frequency of fs/2) gives exact reconstruction at the
Nyquist frequency.