Design and manufacture of lock-in amplifier

Abstract

This design realizes the excellent performance of lock-in amplifier in detecting weak signal, which is composed of signal conditioning circuit and MCU control module. The single chip microcomputer is used to control the AD sampling of the filtered DC component after multiplication operation, and the FPGA is used to realize the phase shift control. Finally, the amplitude of the signal to be measured can be obtained by eliminating the gain generated in the whole circuit with the measured amplitude. After testing, it has the advantages of high sensitivity, high input impedance and low noise, and can realize accurate measurement.