Digital Readout System for Micromachined Gyroscope and Analysis for its Demodulation Algorithm

A new digital readout system for micromachined gyroscope has been proposed to implement flexible parameter adjustment, improve the control performance of gyroscope, and make error compensation. By digitalizing the output of the gyroscope, this system uses a floating-type digital signal processor (DSP) to process the signal demodulation and achieve the feedback control of the gyroscope. Therefore, the small change of capacitance in the micromachined gyroscope can be detected. A new demodulation algorithm of least mean square demodulation (LMSD) has been developed inside DSP. Simulation and measurement results show that LMSD can improve 29% of the noise performance compared with the typical multiplication method. In air pressure, a kind of vibration-wheel micromachined gyroscope has achieved a noise level of 0.0073 deg s(-1) . Hz(-1/2) over the 100-Hz bandwidth by using this digital readout technology.