Path: utzoo!attcan!uunet!ginosko!uakari.primate.wisc.edu!ames!pasteur!ucbvax!hplabs!hpl-opus!hpnmdla!hpsad!toma
From: toma@hpsad.HP.COM (Tom Anderson)
Newsgroups: comp.dsp
Subject: Re: Re: Digital Mixer Using Burr-Brown 200 Khz ADC (Ooops!)
Message-ID: <9520006@hpsad.HP.COM>
Date: 1 Oct 89 05:51:13 GMT
References: <8388@sunspot.megatest.UUCP>
Organization: HP Signal Analysis Division - Rohnert Park, CA
Lines: 21

>byron@pyr.gatech.EDU (Byron A Jeff) writes:
>
>-----------  ---------  ---------  --------   --------  --------  --------
>|8        |--|Analog |--|Filters|--|      |---|      |  |      |  |      |
>|Audio    |--|Multi- |  |  and  |  | ADC  |   | DSP  |--| DAC  |--|Filter|
>|channels |--|plexors|--|  S/H  |--|      |---|      |  |      |  |      |
>-----------  ---------  ---------  --------   --------  --------  --------
>           ^^                              ^^^
>     Eight lines here.               There should be two lines since it
>                                     is a dual ADC.
>
It seems to me that the filters need to go on the other side of the mux.
Imagine that for a set of samples the left channel has inputs 1,2,3,4 of
0v,10v,0v,10v respectively.  For a 200kHz A/D, the frequency of this is 
100kHz.  This won't get through a regular audio type anti-aliasing filter.

What are people paying for a digital audio anti-aliasing filter?

Tom Anderson           Hewlett-Packard        Signal Analysis Division
toma@hpsad             "It's only hardware"
Opinions expressed here are my own and not HP's