Sound cards use a small surface mount crystal oscillator for their reference frequency. These oscillators typically have a stability of +/- 100 ppm over a temperature range of -10C to +70C. This is +/- 0.1 Hz at 1000Hz. Which is in the same ballpark as the 0.061 Hz per step at 12 bits. However the sound card is not very likely to see such temperature variations and there are ways of digitally removing offsets and slowly varying drift from the data.


Jim Hannon

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Jim Hannon
http://www.fmtcs.com/web/jmhannon/
42,11.90N,91,39.26W
WB0TXL
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