Design of data acquisition system for micromachined silicon resonant gyroscope based on FPGA

The structure of the micromachined silicon resonant gyroscope was introduced and the relationship between the maximum frequency shift or modulation index and input angular velocity signal was presented. According to the analysis of the electrostatic comb-finger driving-force of the sensitive proof mass and the output signal of double-ended tuning fork (DETF) resonator, the relationship between phase difference of output signal of DETF and modulation index was obtained. A detection method for maximum frequency shift was proposed, in which phase difference was calculated for computation of modulation index or the maximum frequency shift so that the input angular velocity could be obtained. Based on this method, a digital demodulation scheme using field programmable gate array(FPGA) was designed and experiments were carried out on the maximum frequency shift detecting circuit based on FPGA. The experimental results show that the circuit is feasible to measure the maximum frequency shift and has excellent measurement effect.