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From: mpurtell@iastate.edu (Purtell Michael J)
Newsgroups: sci.electronics,comp.dsp
Subject: Re: A question about the Nyquist theorm
Message-ID: <1991Mar1.080014.19415@news.iastate.edu>
Date: 1 Mar 91 08:00:14 GMT
References: <625@ctycal.UUCP> <11515@pasteur.Berkeley.EDU> <1991Feb28.084837.7506@appmag.com>
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In article <1991Feb28.084837.7506@appmag.com> appmag!todd@hub.ucsb.edu writes:
>jbuck@galileo.berkeley.edu (Joe Buck) writes:
>
>%Example of CD salespeak: pushing oversampling as an advanced technical
>%feature.  Oversampling is simply inserting zeros between the digital
>%samples and thus increasing the sampling rate.  It's used because then you
>%can use cheaper, less complex analog filters; it reduces the system cost.
>%Still, some sales critters think it's an advanced technical extra.
>
>Not all CD players just insert zeroes.  I used the same double oversampling
>chip and the same DAC as my Denon 1500 CD player (well, I used the serial
>versions) in my 56000 project board.  The oversampling chip did do
>interpolation (and it was slightly more complex than bilinear (cubic spline?
>I don't remember)).

A Singnetics chip I've seen that does oversampling does sinusoidal
interpolation in addition to interpolation in the case of uncorrectable
errors in the data stream (from a CD).  

If you're going to have interpolation for errors, which I think IS important,
you might as well do it for oversampling too, even if you can't hear the
difference.  If nothing else it eases the constraints on the output filter.
-- 
-- Michael Purtell --  | "In a hundred years, | There's an Old Irish Recipe for
mpurtell@iastate.edu   |  we'll all be dead." |   Longevity: Leave the Table
Iowa State University  |  -- The January Man  |  Hungry.  Leave the Bed Sleepy.
                "slow is real"                |    Leave the Tavern Thirsty.