I am trying to monitor a line level signal (sound card 3.5mm stereo out) using an AVR ADC to assign values to the varying amplitude curve over time.
I don't understand how to get the signal. If I monitor it with a voltmeter, I see nothing. If I use a software oscilloscope looped back into the soundcard input, I see the wave from -1 to +1V. There is obviously something going on in between.
Can someone help out? Thanks.