中文摘要：

差动电容传感器已广泛地应用于压力、压差、位移、加速度、振动等非电量的精密测量，参比电容传感器有望用于煤粉浓度测量等领域，而微小电容测量电路是电容传感器应用中的核心和关键技术。微小电容测量的难点在于杂散电容的存在以及电磁干扰，而交流激励电容测量电路可以采用调制解调方式将缓慢变化的电容传感器信号调制在激励源提供的高频载波上，有效抑制同频干扰，工频干扰，运算放大器的失调电压和失调电流，电阻电容等器件的低频噪声干扰。在活塞压力平台上对交流激励电容测量电路进行了性能测试。结果表明，交流激励电容测量电路迟滞误差为0．19％，非线性误差为0．23％，重复性误差为0．29％，可应用于参比电容传感器测量系统。

英文摘要：

Different capacitance sensor has doyde a very important role in the precision measurement of pressure, differential pressure, displacement, acceleration and vibration, and reference capacitance sensor pulverized coal concentration, and the small capacitance measuring circuit is the core and key technologies of a capacitance sensor applications, the difficulty of capacitance Measuring lies in the presence of stray capacitance and electromagnetic interference, and the ac excitation of the capacitance measuring circuit can be used modulation and demodulation of the slow changes in capacitance sensor signal modulation in the high-frequency carrier excitation source, the effective inhibition of the same frequency interference, frequency interference, the operational amplifier offset voltage and offset current, Low frequency noise interference of resistors and capacitors, etc. On the piston pressure Calibration stage to conduct a performance test of switched-capacitor interface circuit. The results show that the switched capacitor interface circuit hysteresis error of 0.19%, nonlinearity error is 0.23%, repeatability error is 0.29%.