Re-post for user: Jackie This question was inadvertently rejected
I found a DC offset in ADC data.
I connect a moving-coil microphone to ADC via a 10uF cap( of course there is an amplifier , and an in-serial 18K resistor). After linear gain - EQ - volume control - ....flow, by the end sent to an uC. No DC control in the schematic. We can see an DC offset in the signal. I want know where it comes from? Thank you.