[Kenwood] PSK31 and sound card sampling rate.

Wed, 3 Apr 2002 19:15:56 -0800

Hi John, sorry to disappoint you but the sampling rate is usually buried in
the guts of the DSP code. Moe Wheatley's original WinPSK program sampled at
11025, but he changed it to 8000 for the DLL because a) not all soundcards
can handle 11025 (in this day and age???), b) the Nyquist cutoff frequency
of 5512.5 Hz vs 4000 Hz isn't much, and c) most receivers don't even make it
up to 4000 Hz anyway. I know you were asking about the 8000 Hz sample rate,
but this is just a little background.

Anyway, as I said, the sample rate is typically hard coded since there are
so many places in the DSP and FFT computations where it's used. Being a
variable would add more run-time computation time, v.s. precalculated values
at compile-time, so hardcoding the sample rate make the program execute more
efficiently. I recall seeing at least one PSK31 program that provided
selectable sample rates, but I can't recall which one at the moment.

So, there's about all I know about it.

73,
-- Dave, WA0TTN
http://www.netdave.com/wa0ttn

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of
> [email protected]
> Sent: Wednesday, April 03, 2002 12:48 PM
> To: [email protected]; [email protected]
> Subject: [Kenwood] PSK31 and sound card sampling rate.
>
>
> Can some one tell me how to set the sound card sampling rate
> to 8000 rather than 11025?
> Seems DigiPan likes 11025 and WINPSK.Dll (Dx4Win) likes 8000.
> Unless WinPSK.dll sets it
> automatically. If so how does one check to make sure it did?
>
> Regards,
> JohnB
> K1JEB
>
>
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