Micro-mechanical (mems) Gyroscope External Digital Signal Processing System

As the research of MEMS technology developed and the performance of the system improved, MEMS becomes a very important aspect in the nowadays high technology competition. MEMS gyroscope is one of the most basilic applications, which are applied to automobile industry broadly. As the precision and stability of MEMS gyroscope improved, MEMS gyroscope plays a very important role in the navigation and military fields. But the domestic research of MEMS gyroscope is in a preliminary stage.The main task of this paper is to design and realize the digital processing system of vibratory MEMS gyroscope signal. Before introducing the system, there are some analyses of the Coriolis Effect which is the basic theory of vibratory gyroscope, then some introduction of the detection principium of angle velocity.The digital system is based on analog processing system. This system includes two modes, drive mode and sense mode. On the analyses of the self-excitation driven loop, the function of AGC (automatic gain control) has been introduced and a new digital AGC algorithm with high control precision has been proposed. Then the improvement in the demodulation of sense mode has been put forward, and the noise analysis of a 16-bit digital system implies a maximum SNR of the output signal.The whole gyroscope is made up of three sections, the gyro chip, the digital processing part and the analog interface circuit. The analog interface circuit provides an interface between the gyro chip and the digital processing part. The implement of the digital processing part is on the FPGA and DSP. The carrier wave is generated in the FPGA and the demodulation of the carrier wave is accomplished with Cordic algorithm in the FPGA. The models of AGC, phase shift and the angular-rotation-rate demodulation are accomplished in the DSP.The performance of the digital system is tested in the end. The testing is referred to the carrier wave, AGC, driven loop signal, and the angular-rotation-rate demodulation model. The accomplishment of this system is a foundation for the further study of MEMS gyroscope digital processing system and the improvement of the processing algorithm.