多路微小平面线圈信号检测系统的设计与实现

Design and implementation of multi-channel signal detection system for small planar coils

为了解决电感值微小(一般只有1μH)、电阻值相对较大、品质因素小的平面线圈难以起振的问题,设计了一个基于改进型克拉泼振荡电路的多路平面电感线圈信号检测系统。系统采用分时扫描技术对多路信号进行多周期同步测频,并利用USB协议进行数据传输。检测结果表明,对电感值在0.5～1.77μH的平面线圈阵列,该检测系统可以提取1 nH量级的电感变化信号,且在1 s内可以完成42路平面电感线圈信号的检测。系统软件部分基于虚拟仪器技术建立,具有灵活性和扩展性。

It is difficult to start oscillation for the planar coils, because of their small inductance of 1 μH, relatively large resistance and low Q-factor. A multi-channel signal detection system for planar inductance coils is presented based on an improved Clapp oscillatory circuit. With USB data transmission, the system uses time sharing scanning multiplexing method for multi-period synchronous frequency measurement. The experimental results show that the systern can pick-up the alteration of magnitude order of 1 nH for the inductance parameter of the planar inductance coil array, which have the inductance range between 0.5 and 1.77 μH, and can realize the measurement of 42 channels within 1 s. The software of the system is developed based on virtual instruments technology and achieves a good flexibility and extensibility.