Howdy - Some of us are poor, so we can't afford a fancy oscilloscope. Here's a link to a pretty nifty software version that works with your sound card: http://polly.phys.msu.su/~zeld/oscill.html. I have no affiliation with this site or the author, I just did a search on the Web. Turns out my calibration wasn't too bad! Mike
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Software Oscilloscope
2001-05-18 by Mike Marsh