A Novel Amplitude-Phase Information Extraction Architecture for MEMS Vibratory Gyroscopes Using a Modified Double Side-Band Demodulation Configuration

This work demonstrates a new architecture adopting a modified double side-band (MDSB) demodulation configuration to gain drive mode amplitude and phase information. Compared to conventional double side-band (DSB) demodulation configuration, it is robust against phase variation of capacitance-to-voltage (CV) interface circuit caused by environmental parameter changes. Theoretical analysis for gyroscopes using MDSB reveals that the amplitude information for AGC loop and phase information for PLL are both independent of the phase delay of CV circuit. Further, the exact phase delay information of CV circuit using MDSB is also extracted which serves as temperature information of the circuit self-heating process. Comparative experiments of the same gyroscope based on MDSB and DSB configurations in drive mode are conducted using a fully decoupled MEMS tuning fork gyroscope. Experimental results indicate that bias drift including the power-on process using MDSB is improved by about 3 times.