Weak signal detection circuit based on lock-in amplifier
Bingwen Wang · Electronic Design Engineering · 2013
In view of that the present lock-in amplifier is expensive and its volume is large,and the performance and flexibility of the traditional narrow-band filtering method is bad,design a weak signal detection circuit based on the principle of lock-in amplifier.This circuit use a MCU as drive signal and reference signal generator,and use op-amp with shutdown pin to realize phase sensitive detector.Experiments show that this circuit can achieved the purpose of extracting useful signal from a signal with SNR of 0.1,the total measuring error is within 5%.Because the circuit is simple and low cost,it’s easy to be use in other measurement system with slight modification.