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RE: 38.4kbps sound card DSP demodulator



Yes.  The SDR-1000 uses 96 Khz sampling already (it is in the form
of 48 Khz complex but that is equivalent) and we consume it and I
do a full fledged synchronous AM detector and a second order PLL for
FM detection and when running those, use 5% of a 3.4 Ghz Pentium
hyperthread.  Others run the same code on 667 Mhz Pentium III's
and use < 50% of that processor for the DSP in the signal chain.
Those that do loads of graphics (spectral displays at impossible
rates) find themselves processor (both SIMD and graphics processor)
starved.  The adaptive LMS filters in the SDR-1000 are 128 taps!!
That is longer than you would need for the link since there is
not a scenario I can think of that would give you a 58 baud
impulse response that means anything on this link.

Yet another project I would love to do without the time to do it.

Bob


-----Original Message-----
From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
Behalf Of Howard Long
Sent: Wednesday, October 06, 2004 11:24 AM
To: amsat-bb@AMSAT.Org
Subject: [amsat-bb] 38.4kbps sound card DSP demodulator


Is this possible?

For example, I have a Soundblaster Audigy 2 apparently with the ability to
resolve 192kHz stereo sound (and 96kHz in 6 channels).

So DSP experts, can a 38.4kbps G3RUH demodulator be written with these
higher sampling rate devices?

73 Howard G6LVB
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