Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!samsung!rex!uflorida!shark!tomh
From: tomh.bbs@shark.cs.fau.edu (Tom Holroyd)
Newsgroups: comp.dsp
Subject: Re: Autocorrelation Pitch Tracker
Message-ID: <9aV7Z2w163w@shark.cs.fau.edu>
Date: 10 Apr 91 13:00:19 GMT
References: <18057@sdcc6.ucsd.edu>
Sender: bbs@cs.fau.edu (Waffle BBS)
Organization: Florida Atlantic University
Lines: 22

> I agree except that the text I'm using uses the two terms
> interchangably.
Doesn't mean *you* have to.
> Maybe for a speech signal, the frequency and pitch
> are the same.
No, they aren't.  As Malcolm Slaney has pointed out, pitch is not
even an invariant- many experiments have been conducted which show
that identical stimuli can be perceived as being different*.
Sort of like when you walk from a very loud environment to a quiet one,
voices seem louder than they did in the loud environment.  This is only
an analogy, but the principle here is that what you perceive depends on
the background, your recent past, your auditory organs, etc.

* For example, work done in our lab by Janice Giangrande using pairs
of Shepard tones- the perceived pitch difference between the pair of
tones changes depending on whether the tones are part of an ascending
sequence or a descending one.

Tom Holroyd
Florida Atlantic University
Center for Complex Systems
tomh@bambi.ccs.fau.edu