Development Of Engineering Transient Electromagnetic Detector

Transient electromagnetic detector is depended on transient electromagnetic principle. The principle of transient electromagnetic method is very simple. It is a kind of geophysical detection method in time domain based on the electromagnetic induction. It launches alternating magnetic field (primary magnetic) to underground used with bipolar current pulse transmitter coil. The primary magnetic field will induce eddy current in the ground conductors. The receiving system receives the eddy current magnetic field (secondary field).The collected data is displayed in the LCD screen by software processing or post-processing, to judge underground conductor traits and other relevant information.This topic develop transient electromagnetic instrument based on field programmable gate array (FPGA) EP3C55F484C6N. The transient electromagnetic instrument achieve the collection and processing of magnetic signal with the FPGA as the core.15 channel signal is collected at the same time based on the FPGA. This paper achieves and improves equipment performance indicator of transient electromagnetic detector. The partial function realization of the transient electromagnetic system is explained in details. The Preamplifier module, Signal conditioning circuit module, Signal acquisition module,power supply module, controller module, keyboard display module and data storage delivery module was designed for transient electromagnetic detector. In addition this paper also analyzed transient superposition algorithm and drawing algorithm of data. The basic functions of transient electromagnetic detector are showed. Finally, the results were presented, including the performance test results and field test results with the transient electromagnetic detector. The performance test includes the emission current, the emission current cut-off time, maximum not distorted input signal, the received signal dynamic range measurement, etc. Finally,15 roads signal real-time collection and measurement results were displaying. In this paper, the measurement model adopts the model of mobile and fixed pattern measurement.