What is the purpose of putting attenuation circuit before op-amp input? I cant find the actual reason for this topology. Is there any reason behind it? Why we need to attenuate the incoming signal but at the end we amplify it.
Signal input -> attenuation circuit (reduce incoming signal level) -> op amp input (amplify signal level)
sorry for late response.
I attached my circuit diagram. Basically it just a simple voltage source (from MIC) + bandpass filter with positive rectifier (range within 5KHz bandwidth) and this signal will input to ADC for detection.
Based on circuit below, I confirmed the attenuation and gain
Attenuation level : -15.56dB Gain level : 29dB
If based on above level, can we just set gain of the amplifier to be 13.44dB (gain level - attenuation level)?
I'm thinking to reduce the component used by deleting the attenuation circuit before the amplifier input.