TMR sensor modulation and demodulation system based on improved digital lock-in amplifier

The invention discloses a TMR sensor modulation and demodulation system based on an improved digital lock-in amplifier, and the system comprises a drive circuit which is used for driving a TMR sensor to generate an output signal according to a generated AC drive signal; the amplifying circuit is used for amplifying the output signal of the sensor to obtain an amplified output signal; the band-pass filter circuit is used for filtering the amplified output signal after receiving the amplified output signal; the synchronous sampling circuit is used for synchronously sampling the reference signal and the filtered amplified output signal after receiving the filtered amplified output signal; and the microcontroller is used for carrying out coherent demodulation processing on the sampled data by applying an improved digital phase-locked amplification algorithm after receiving the sampled data. The design of a traditional digital lock-in amplifier is improved, the stability and the reliability of the digital lock-in