Andy.
The clock for the integrated sound chip may be derived from other system
clocks.
Better to disable the internal audio and mess about with a £10 PCI sound
card!
If you're getting ambitious there are quite a few "pro" soundcards out there
which sample up to 96kHz, input filtering is probably quite good at 22kHz
though...
See HHB.co.uk and other pro-audio dealers.
73
Dave
G3YXM.
----- Original Message -----
From: "Talbot Andrew" <[email protected]>
To: <[email protected]>
Sent: Tuesday, March 19, 2002 9:59 AM
Subject: LF: Soundcard Mods
Has anyone tried changing the clock source on a Soundcard for a different
frequency ? For a job here at work we need to sample more accurately
than
the usual crystal oscillator (does this sound familiar ?) and at different
sampling rates. It would be ideal if we could push it to 50kHz, but 25kHz
and 12.5kHz would do, as well as accurate 8 and 16kHz options. One idea
that immediately comes to mind is to remove the Soundcard clock crystal
and
feed in the input from a synthesizer. Before diving inside a PC, I wonder
if anyone has ever tried this ? Modifying the integrated soundcard on the
Dell machines here could prove a bit tricky just to try on spec.
For LF use, how about an externally derived 1kHz sampling rate for input
from receivers using a narrow CW filter and BFO pitch set below 400 Hz ?
Andy G4JNT - but with another hot on now.
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