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Date: Wed, 25 Apr 2001 10:53:18 -0400
To: rsgb_lf_group@blacksheep.org
From: "Bill de Carle" <bill1@cgocable.ca>
Subject: LF: Re: WOLF with Sigma-Delta interface
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At 01:50 PM 4/25/01 +0100, Andy, G4JNT wrote:
>If Jim is coming, perhaps you would be able to give a demo of Wolf ?
>I can demo standard BPSK with the VE2IQ software and interface.
>Hopefully a version of WOLF for use with this will appear eventually.

I don't know if people realize this, but there is an easy way to
use either the VE2IQ S-D interface or Andy's PIC-based interface to
create a file readable by WOLF.

Just use the CRUNCH program without compression (i.e. a time compression
factor of 1.0).  It will create a .WAV file at 7200 samples per second.
If you invoke CRUNCH with the "TIME" option, you can specify a time of
day to start recording and how many minutes to record.  Very nice if
you want to record at some oddball time when you want to be asleep.

Earlier versions of WOLF needed a .WAV file header which specified
8000 samples per second, but I just faked that by changing the indicated
rate in the file header after recording.  I understand later versions
of WOLF should work directly with 7200 s/s .WAV files.  You will, of
course, have to specify the exact sampling rate (-r) when invoking the WOLF program itself.  The SD board samples at 7200 samples per second.  You can  install a trimmer cap on the board (details are available somewhere,
probably on my web page) to tweak it to exactly 7200.00 - or you can just measure the rate and tell WOLF what it is.

If anyone out there ever bothered to set up a GPS 1PPS input to the serial
port's Ring Indicator input pin (talked about here some months ago), I
can e-mail you a program that measures the audio sampling rate to a whole
lot of decimal places.  Works with the SD board and with supported sound
cards.

73 de Bill VE2IQ