电容式微加速度计的噪声分析

噪声是以微弱信号处理为特征的电容式微加速度计性能提高的主要制约因素。针对电容式微加速度计的噪声,详细分析和研究了其特性。首先分析了电容式微加速度计的系统噪声由机械热噪声和电路噪声两部分组成;采用热力学均分理论和集成电路噪声特性分别对机械热噪声和电路噪声进行建模、分析和计算,得到了机械热噪声等效噪声加速度和各级电路的噪声值。然后用自行设计的微加速度计表头和接口电路进行试验,实验结果验证了噪声模型的正确性,确认了电容式微加速度计电容检测电路—电荷放大器是最主要的噪声源。

Synthetic Analysis of Noise in Capacitive Micro-accelerometer

The noises for capacitive micro-accelerometer are the main obstacle to improving its performance.This paper analyzes the noise characteristics of capacitive micro-accelerometer.The noise sources are modeled as mechanical and electrical parts,and of their values in the system are both analyzed and calculated by the theory of thermodynamics equilibrium and the characteristic of integrate circuit noise.From analyzing the result of experiments by capacitive micro-accelerometer which is designed of our own,the charge amplifier noise is the main noise source.The model of noise and conclusion are validated by experiments.