Hero999
Banned
Oh yes you do need a rectifier.
You need a rectifier to get rid of the negitive side first before you can use a low pass filter. This is exactly the same as tuning into an AM radio station, to get the audio superimposed on the RF signal it needs to be rectified before you do anything else.
I suggested an amplifier because at such low voltages the input ofset error and linear region of a comparator might start to become issues, an amplifier will help make it more stable, although it isn't essential.
If does need a rectifier as the signal consists of both positive and negitive components, stick an RC filter on the end and you'll loose everything as the positive and negitive sides will cancel.ericgibbs said:It also dosn't need a rectifier, just a simple RC filter on the comparator output
You need a rectifier to get rid of the negitive side first before you can use a low pass filter. This is exactly the same as tuning into an AM radio station, to get the audio superimposed on the RF signal it needs to be rectified before you do anything else.
I suggested an amplifier because at such low voltages the input ofset error and linear region of a comparator might start to become issues, an amplifier will help make it more stable, although it isn't essential.