谐振式微加速度计差频检测电路研究

Study on the Difference Frequency Circuit of MEMS Resonant Accelerometer

微机械谐振式加速度计的输出频率信号不易受到环境噪声的干扰,在传输和处理过程中也不易出现误差。针对实验室加工的谐振式微机械加速度传感器,采用静电激励和电容拾振的检测方式,设计了电容拾振检测电路和差频输出电路,实现了谐振式加速度计的微弱差频信号检测。利用精密分度盘对该加速度传感器进行了性能测试,实验室测试灵敏度为25.7 Hz/g,达到了设计要求。

It is requested that the output frequency signals of the resonant accelerometer are not easy to be interfered by the environmental noises and to be generated errors during the signal transmission and processing. The electrostatic driving and capacitance pick-up methods were adopted to detect the resonant accelerometer. The capacitance pick-up circuit and the difference frequency output circuit were designed to detect the weak difference frequency signal of the resonant accelerometer. The precision protractor was used to test the performance of the accelerometer. As the experiment shown, the sensitivity of the accelerometer is up to 25.7 Hz/g.