[Lf] Soundcards

[Frank Gentges K0BRA]

Vittorio,

You are right about getting the ADC out of the computer box.  A friend built
a high end DSP board for the PC and put the ADC outboard with an interface
he designed to the digital processing inside the PC.  He was able to get a
full 16 bit signal to noise but only with some effort.  Getting 24 bits may
be almost too hard based on his work.  You can check out his web site at
<http://www.swva.net/mtnaudio> to see more.

On the road at Flagstaff Arizona tonight.

Frank K0BRA

-----Original Message-----
From: Vittorio De Tomasi <vdetomasi at tiscalinet.it>
To: lf-amrad <lf at amrad.org>
Date: Tuesday, February 08, 2000 11:19 PM
Subject: [Lf] Soundcards


>
>
>Hi,
>
>Some questions were raised about sound cards quality in past messages.
>At URL http://www.rockpark.com/soundcards/ you can find some
>measurements on some brands of sound cards. Maybe they are not very well
>suited for Hi-Fi applications, but they look good for ham radio work...
>
>However I think we should look for two improvements in sound card
>systems: USB sound cards and 24 bit recording (maybe both in the same
>device...).
>
>A sound card connected to an USB bus should allow us to keep the ADC
>very far from switching circuits (CPU, power supply, ...), thus probably
>reducing the spurious lines we all see in our background spectra).
>
>24 bit recording can give us enough dynamic to allow us to switch AGC
>off, and to directly digitize IF signals (converted to a suitable IF
>frequency) without worrying for saturation.
>
>However I wonder if the market will ever come out with a cheap solution:
>we should probably look at USB development systems (like the one sold by
>Cypress Semiconductors), and think about wiring a 24 bit ADC to it...
>
>
>vy 73
>
>Vittorio ik2czl
>--
>*************************************************************************
>Vittorio De Tomasi         ik2czl at amsat.org
>Home page:                 http://space.tin.it/scienza/vdetomas
>My DSP page:               http://www.freeyellow.com/members/padan
>
>"You dialed an imaginary number.
>Please rotate your telephone of 90 degrees and redial".
>
>
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