The output signal components of the sensitive end of micro-electro-mechanical system (MEMS) gyroscope are complex, and the design error of the back-end demodulation circuit can greatly affect the detection accuracy of the gyroscope. Therefore, this paper designs a high-precision signal demodulation scheme applicable to MEMS gyroscope sensors. The scheme improves the traditional signal demodulation technology by combining the correlation demodulation technology and the fast Fourier transform (FFT) technology, and after the correlation demodulation of the gyroscope-sensitive signal, the infinite impulse response (IIR) filter and the FFT transform are used to jointly extract the amplitude information of the fundamental frequency signal and do the fusion processing, so as to achieve the very high precision extraction of the input angular velocity. The feasibility of the demodulation scheme is verified by field programmable gate array (FPGA) simulation. The experimental results show that the combined IIR and FFT filtering algorithm has higher demodulation accuracy than the single low-pass finite impulse response (FIR) filtering algorithm.

MEMS gyroscope;switch demodulation;digital low-pass filter;fast Fourier transform