Design For Digital Signal Processing Circuit Of Digital Gyroscope

Recently, the digital integrated circuit technology of MEMS gyroscope has become a hot topic all around the world. There are many advantages if using digital technology to design the gyroscope interface circuit. For example,anti-interference ability, high accuracy, easy distortion,high reliability and so on. So, the paper brings out a digital interface circuit designing that based on analyzing the principle of driving mode and sensing mode and phase characters of digital silicon gyroscopes.The circuit design part of this article includes three modules, which are signal generating module, data processing module and signal conversion module. The signal generating module uses direct digital synthesis technology to generate sine and cosine signal. Taking logic resource usage and data processing speed into account, the data processing module adopts radix-2 decimation-in-time fast Fourier transform algorithm for data collecting and calculating. The signal conversion circuit completes with AD5546, AD7666, LM358 and other chips.Then building the system model of digital algorithm with the Matlab determines the performance indicators. The input frequency is 1MHz, the sampling frequency is 100 KHz, the sampling depth of FFT algorithm is 214. Each module is designed by Verilog code and IP core which is configured by ISE13.3. And functional simulation is confirmed by Modelsim and ISE13.3. The frequency of sine is 4KHz, and same as cosine. The total calculated time of data processing module is about 166.55 ms.The hardware development system includes user defined IP core and hardware platform, which is constructed by Micro Blaze soft-core. The system is controlled by C language to achieve intended function. And using Chip Scope software crawls the result during the board-level verification, and gets 4KHz sine and cosine wave. The esonant frequency and angular velocity reach to 3999.9Hz, with detection accuracy smaller than 0.1.