Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hp-pcd!hplsla!tomb
From: tomb@hplsla.HP.COM (Tom Bruhns)
Newsgroups: sci.electronics
Subject: Re: Audio Spectrum Analyzer chips wanted
Message-ID: <5170027@hplsla.HP.COM>
Date: 1 May 89 18:45:01 GMT
References: <7958@killer.Dallas.TX.US>
Organization: HP Lake Stevens, WA
Lines: 38

>I am interested in any information on chips that would facilitate construction
>of an audio-range spectrum analyzer.  The ideal solution would be a single
>chip that could be accessed n-times a second and provide a computer a word or
>words in which each bit represents a frequency range, and the "on" condition
>would represent the signal at that range going above a preset threshold during
>the time-slice involved....however, any chip or set of chips that could do
>the same for a single frequency range would probably do.
>
>The application, by the way, is a computer-displayed voiceprint...Fourier
>Analysis is just too slow.

I submit that it isn't the Fourier Analysis that's too slow -- it's your
implementation of it.  Try it on a DSP chip.  You should be able to do
this easily with a Texas Instruments TMS320 or Motorola 56000 or ... .
BTW, easily refers to the capacity of the chip to do it, not the ease of
programming it or building it!  Either chip should be able to do an FFT
of a 1024-point input record fast enough to keep up with over 10000 
samples per second; another way to do it is to program digital filters
for the bands you want, to avoid the FFT's constant-width-per-bin.

You can also get cards to slip into a PC to do this sort of thing.  Ariel
in New Jersey comes to mind; I don't have their address handy.  Or you can
rent or buy an FFT analyzer from my employer or (heaven forbid)) a
competitor.


>
>Thanks.........
>
>-- 
>+-------------------------+ +-----------------------------------------------+
>| Lance T Franklin        | | I never said that! It must be some kind of a  |
>| ltf@killer.DALLAS.TX.US | | forgery...I gotta change that password again. |
>+-------------------------+ +-----------------------------------------------+
>----------

Tom Bruhns
tomb%hplsla@hplabs.hp.com