Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 5/3/83; site utcsrgv.UUCP
Path: utzoo!utcsrgv!spoo
From: spoo@utcsrgv.UUCP (Suk Lee)
Newsgroups: net.audio
Subject: Re: 20kHz Square Waves -- GIVE ME A BREAK!!!!
Message-ID: <4659@utcsrgv.UUCP>
Date: Thu, 28-Jun-84 12:55:43 EDT
Article-I.D.: utcsrgv.4659
Posted: Thu Jun 28 12:55:43 1984
Date-Received: Thu, 28-Jun-84 13:27:14 EDT
References: <1361@pur-phy.UUCP>
Organization: CSRI, University of Toronto
Lines: 30

> by the D/A converter.  Sampling at 44kHz, a 22kHz square wave can be reproduced
> exactly (alternate samples are a high voltage then a low voltage).

I can't believe the utter nonsense 
that's been coming out of this group
on this subject.  The person fed a 
alternating series of samples at 
22 kHz. into a D/A, observed the RAW
output (no filtering) and them made
the above claim.  The point of the
low-pass filter (NOT THE ANTI-ALIASING
ONE) after the D/A conversion is to
interpolate between the instantaneous
samples and give you a continuous
waveform.  The person who did the
"experiment" did not do so and his
arguements are invalid -- the samples
he fed into his D/A are indistinguishable
from those of a 22kHz. sine wave, and
yet he got a "square wave" out -- 
because he didn't set up his experiment
properly.  And this from a Physics
Department!!!!  Ack!!!!!!!!
-- 

From the pooped paws of:
Suk Lee
..!{decvax,linus,allegra,ihnp4}!utcsrgv!spoo