Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!gem.mps.ohio-state.edu!apple!jef
From: jef@Apple.COM (Jonathan Flamm)
Newsgroups: comp.dsp
Subject: Re: oversampling
Message-ID: <35056@apple.Apple.COM>
Date: 27 Sep 89 03:27:33 GMT
References: <1122@rex.cs.tulane.edu>
Distribution: usa
Organization: Apple Computer Inc, Cupertino, CA
Lines: 16

In article <1122@rex.cs.tulane.edu> hoang@rex.UUCP (Dzung Hoang) writes:
>	My DSP professor discussed CD oversampling and his explanation was
>different from the above in the details.  Oversampling does not directly
>interpolate the sample values to 47 47.25 47.5, etc.  Instead, 0's are
>inserted as appropriate between samples.  The LPF takes care of recovering
>the signal.  There is no distortion at all.
>
>Dzung Hoang

Actually zeroes are inserted but interpolation is performed using a digital
filter -- hence the jargon "digital filtering" so prevelant on CD players.
The LPF is done (as usual) in the analog domain and can be accomplished
with a much shallower, more linear filter.  At least this is what I believed
to be true.
Jonathan Flamm
jef@apple.com