Hello everybody, using a PIC 8 bit, I need to sense the voltage variation at the output of a position transmitter with the intention of plot it vs position using a PC, the signal is ±4 V 400 HZ, the variation from the initial position to full stroke is about 1.5 to 3.5 Vrms. I am getting a sample of the signal using the ADC module, but I need the Vrms or peak voltage. How can I do to do it? How can I condition the signal? Should convert the signal to DC?, How can I convert the signal to DC while maintaining it proportional to the variations of the input signal. Thanks for your help and time.

 

Look up precision rectifier.