Message-ID: <001001c0b253$2c726ca0$09dc9384@ma.ultranet.com>
From: "John Andrews" <w1tag@charter.net>
To: rsgb_lf_group@blacksheep.org
References: <5186.200103191301@gemini>
Subject: LF: Sound card sample rate cal for WOLF
Date: Wed, 21 Mar 2001 17:05:55 -0500
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In a quick experiment this morning, I recorded 15 minutes of LORAN-C with my
receiver in AM mode. The recording was done with my normal WOLF setup, 8000
Hz sampling, 16 bit. My "local" LORAN-C station has a 9960 microsecond
repetition rate, which is 100.4016 Hz. I then set WOLF to measure the 8th
harmonic of that rate, as follows:
wolf -f 803.21285 -q (filename.wav) -m 60

WOLF then nicely gave me a list of frequency offsets measured every 60
seconds. In my case, the offset was -0.197 Hz, which yielded 8001.96 Hz for
the sampling rate. This agrees very closely with measurements made with an
accurate 1 kHz tone. The calculation has been described earlier on this
list:
8000(803.21285 / (803.21285 - 0.197)) = 8001.96

This method relieves the need for an accurate tone source. It also uses your
normal WOLF recording and crunching software and sampling rate. You do need
to know a repetition rate for a LORAN-C signal in your receiver's output.

John Andrews, W1TAG