基于大尺度传感器的电容测量电路抗干扰方法  

Anti-interference method for capacitance measuring circuit based on large scale sensor

作　　者：赵进创[1] 王祎[1] 傅文利[1] 邹星星[1] 

机构地区：[1]广西大学计算机与电子信息学院,广西南宁530004

出　　处：《传感器与微系统》2016年第8期24-26,29,共4页Transducer and Microsystem Technologies

基　　金：国家自然科学基金资助项目(61362025)

摘　　要：为了抑制基于大尺度传感器的电容层析成像(ECT)系统的电容测量电路中的较强测量干扰,在分析了测量电路中单屏蔽同轴电缆和模拟开关杂散电容测量干扰产生机理的基础上,设计了能抗杂散电容的基于等电位驱动电缆内屏蔽技术和双T型模拟开关阵列的大尺度传感器电容层析成像系统测量电路,同时,为了提高测量电路输出信噪比,在测量过程中采用双极板激励策略增强大尺度传感器内敏感场强度。经实验测量,采用该抗干扰方法的电容测量电路的输出信噪比为56.8 d B,10 h内测量值标准差为0.132 f F。可见,该电路抗杂散电容干扰能力较强,输出信噪比较高,稳定性较好。In order to suppress strong measuring interferences in measuring circuit of electrical capacitance tomography（ ECT） system based on large-scale sensor,on the basis of analysis on stray capacitance interferences produced by single shield coaxial cables and analog switches,stray-immune measuring circuit using cable-driven technology and double-T-switch array is designed to suppress stray capacitance interferences. Meanwhile,in order to improve output signal-to-noise（ SNR） ratio of the measuring circuit,2-electrode excitation strategy is employed to enhance the sensitivity in the sensor. Experimental results show that output SNR of the proposed measuring circuit is 56. 8 d B and the standard deviation of the measured value in 10 h is 0. 132 f F. The proposed measuring circuit has good stray-immune ability,high output SNR and good stability.

关 键 词：电容层析成像 大尺度传感器 杂散电容 等电位驱动 双T型模拟开关阵列 双极板激励 

分 类 号：TP216.1[自动化与计算机技术—检测技术与自动化装置]