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Path: utzoo!watmath!watdcsu!herbie
From: herbie@watdcsu.UUCP (Herb Chong [DCS])
Newsgroups: net.audio
Subject: Re: CD sampling rates
Message-ID: <871@watdcsu.UUCP>
Date: Thu, 24-Jan-85 11:41:52 EST
Article-I.D.: watdcsu.871
Posted: Thu Jan 24 11:41:52 1985
Date-Received: Fri, 25-Jan-85 05:25:23 EST
References: <232@decwrl.UUCP>
Reply-To: herbie@watdcsu.UUCP (Herb Chong [DCS])
Organization: U of Waterloo, Ontario
Lines: 33
Summary: 

In article <232@decwrl.UUCP> joel@decwrl.UUCP (Joel McCormack) writes:
>1)  Music waveforms are NOT sine waves, nor are they COMPOSED of sine
>waves.  Sine waves go on forever, while music changes.  All that stuff
>you learned about Fourier transforms is only approximately related to
>music (on the assumption that sharp transitions take place relatively
>infrequently to the cycle time, and that (aside from sharp attacks) 
>amplitude envelopes look fairly flat against cycle time).  But just 
>because true SINE waves can theoretically be recovered by sampling higher 
>than the Nyquist frequency DOES NOT imply that music (or for that matter,
>any PHYSICAL sort-of-periodic sort-of-waves) can be recovered.

you obviously don't remember a whole lot about Fourier transforms.
Fourier proved that ANY causal signal can be represented as an infinite
sum of sine (or cosine) waves.  music certainly is a causal signal and
a Fourier transform is a complete representation of any such signal.
whether the signal is periodic or not is irrelevant.  it just changes the
limits on the Fourier integral.  

BTW, for those who read my posting of BAUD vs. bits/s, i apologize for
having the definitions exactly reversed. 

Herb Chong, BASc
Computer Consultant 

I'm user-friendly -- I don't byte, I nybble....

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