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Weird rms voltage reading using BIP Sine Wave Generator 3.0

Twigg

Nov 23, 2011
4
Joined
Nov 23, 2011
Messages
4
Hi all, I'm a newbie here. I was experimenting with BIP Sine Wave Generator 3.0, a piece of open sourceware that uses a computer's sound card to generate analog signals, and the signal I picked up was weird.
The first thing I tried was I used an oscilloscope program from the same people, BIP Oscilloscope 3.0, to read the output signal. I ran a cord from the headphone jack to the microphone jack on my computer, using both programs at the same time. My computer has a CODEC with a 5V rating. At the 6Hz setting, the signal looked more like a bar code than a waveform (max voltage 5V). I thought maybe the program worked this way by timing the 5V blips to average out to a waveform, so I tried measuring the rms voltage of the signal. I ran a cord out of the headphone jack, and hooked it up to a Fluke true rms multimeter. The voltage reading kept flicking back and forth from 0 to 2.2ish mV (I kept the computer's volume settings the same as in the first test, and tested this at frequencies ranging from 4Hz to 40kHz). I'm not sure what it is I'm seeing. Is this normal for converted analog signals?
 

Twigg

Nov 23, 2011
4
Joined
Nov 23, 2011
Messages
4
Nevermind on the rms readings. I just realized that I'm an idiot and I had the output of the signal set to my laptop's speakers. *facepalm*
 

davenn

Moderator
Sep 5, 2009
14,254
Joined
Sep 5, 2009
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14,254
hi Twigg
welcome to the forums :)

good you discovered the problem, we all do that sort of thing from time to time lol

Dave
 
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