数模混合式微机械加速度计系统仿真与优化

Simulation and optimization of digital-analog hybrid micromachined accelerometer system

为了提高基于栅结构电容检测式微机械加速度传感器的数模混合式系统的检测精度,在Simulink仿真平台上建立系统仿真模型,用以分析影响系统输出端噪声性能的主要因素。仿真结果表明通过增大载波信号幅度、减小仪表放大电路的增益能够优化数模混合式微机械加速度计系统的噪声性能。实验测试数据显示,当载波信号幅度为14V、仪表放大电路增益为1时,系统噪声等效加速度为3.054μg/Hz(1/2),为优化前的0.256倍。

In order to improve the precision of the digital-analog hybrid system based on the fence structure capacitive sensing micromachined accelerometer, a system simulation model is built on Simulink. The main noise which affects the system noise performance can be found by the model. Meanwhile, the digital-analog hybrid micromachined accelerometer system can be optimized by increasing the amplitude of the carrier wave and decreasing the gain of the instrumentation ampli- fier based on this simulation model. The test results show that when the amplitude of the carrier wave is 14V and the gain of the instrumentation amplifier equals to 1, the output noise equivalent acceleration of the optimized system reaches to 3. 054 μg/√Hz, which is 0. 256 times as before.