瞬变电磁实验教学模型系统设计

针对地学仪器课程中瞬变电磁仪的实践教学需要，设计了一套瞬变电磁实验教学模型系统。该系统包括 发射/接收一体机、接收传感器、异常线圈和上位机控制软件4 部分。发射/接收一体机使用AＲM( Advanced ＲISC Machine) 控制器和CPLD( Complex Programmable Logic Device) 作为主控单元，驱动H 型全桥电路实现双极 性方波的产生与发射; 利用差分式空心线圈和双运放仪用放大电路设计了高灵敏度传感器; 通过研究闭合线圈 感应电动势与时间常数的关系，使用异常线圈模拟了良导电率有限导体; 上位机控制软件使用C#语言在Visual Studio 平台上开发。经测试，该模型能实时采集并显示瞬变电磁感应二次场衰减信号曲线，实现在实验室内模 拟瞬变电磁仪工作过程，对课程的实践教学具有一定的辅助作用。

Design of Transient Electromagnetic Experiment Teaching Model System

In order to meet the practical teaching needs of the geoscience instrument course，a transient electromagnetic experiment teaching model system is designed． It includes four parts: a transmitting /receiving integrated machine，a receiving sensor，an abnormal coil and a host computer control software． The transmitting / receiving integrated machine uses the AＲM ( Advanced ＲISC Machine ) controller and CPLD ( Complex Programmable Logic Device) as the main control unit，and drives the H-type full-bridge circuit to realize the generation and transmission of a bipolar square wave． The high-sensitivity is designed using the differential hollow coil and the amplifier circuit for the dual op amp sensor． By studying the relationship between the induced electromotive force of the closed coil and the time constant，an abnormal coil is used to simulate a good conductive finite conductor． The host computer control software is developed on the Visual Studio platform using C # language． After testing，this model can collect and display the transient electromagnetic induction secondary field attenuation signal curve in real time，realize the simulation of the working process of the transient electromagnetic instrument in the laboratory，and have a certain auxiliary effect on the practical teaching of the course．