| 1. | According to the electromagnetic induction theory , abrupt variation of current in the transmitter loop will induce magnetic field around it , which is called the first field . in the transmission of the first field , when it meets good conductor target , induce current will be created , which is called erratic current of second current . because the second current changes with time , so it will create new magnetic field , which is called 对于接收部分,由于瞬变信号具有早期信号幅度大、衰减快,而中晚期信号幅度小、衰减慢的大动态范围的特点,必须设计适应这种大动态范围信号的采集电路;为了适应野外工作,系统主控部分采用具有功耗低、高速处理的dsp ,通过高速通用串行接口usb与上位机通讯,实现对整个探测系统的控制。 |