MEMS gyroscope control system using a band-pass continuous-time sigma-delta modulator

This paper presents a MEMS gyroscope control system based on a band-pass continuous-time sigma-delta modulator (ΣΔM). Compared with a low-pass discrete-time based solution, it enables a circuit implementation at a much reduced sampling frequency; therefore can be easily implemented in hardware using standard off-the-shelf electronic components. System level simulations using Simulink show the proposed sixth order electromechanical ΣΔM can achieve a high SNR of 100 dB at a full scale input signal of 200°/s. Measurement of the power spectral density of the output bitstream reveals a noise floor of -90dBV/Hz^1/2. The prototype is tested on a rate table with an angular signal, verifying that the principle of the approach using an electro mechanical band-pass ΣΔM control system for a MEMS gyroscope.