基于摆式重力仪的电容测微相敏检波器研究

Research on Micro Capacitance Sensor and Phase Sensitive Detector Based on Pendulous Gravimeter

基于摆式重力仪的基本结构,分析了重力检测电容测微器的工作原理,同时提出了一种提供电容测微器激励信号的高对称差分激励信号源的设计。针对微弱信号检测环节,根据互相关检测数学模型,设计了一种实用型开关式全波相敏检波电路。本文电路已在摆式重力仪设计研制中获得成功应用,结果表明:电路性能稳定,检测精度优于20μV,重力检测精度优于1×10-6ms-2(0.1 mGal)。

Based on the basic structure of the pendulous gravimeter, the principle of micro capacitance sensor was analyzed and a new method for the differential excitation signal generator of micro capacitance sensor was introduced, this signal generator could provide exceptional output balance. According to the principle of weak signal detection based on cross correlation technology, a new circuit for the switching-mode phase sensitive detector was deployed in the pendulous gravimeter. The experimental results showed that the circuit was high stability and the measuring accuracy was better than the level of 20μV, the measuring accuracy of gravimeter was better than the level of 1 × 10^-6ms^-2 （0. 1mGal）.