【作者】 张琳琳；

【导师】 张爽；

【作者基本信息】 吉林大学 ， 集成电路工程（专业学位）， 2016， 硕士

【摘要】 瞬变电磁探测仪是依靠瞬变电磁法原理研制的一种探测仪器。瞬变电磁法的原理很简单,是一种以电磁感应为基础的时间域的地球物理探测方法,它利用发射线圈向地下发射交变磁场(一次场),发射线圈通有双极性电流脉冲,该一次场将在地下导体内感应出涡流,涡流产生的磁场(二次场)被接收系统接收,将采集到的数据进行后期处理,或者通过主控进行一系列的信号处理,最后通过液晶屏以图形的形式显示出来,由此判断地下导体的性状等相关信息。本课题研制了一种基于现场可编程门阵列(FPGA) EP3C55F484C6N的瞬变电磁探测仪。此瞬变电磁探测仪是以FPGA为主控核心实现了磁场信号的采集和处理,采用基于FPGA的软件设计对信号进行15通道的同时采集。本文首先介绍了瞬变电磁探测仪的基本原理,整个系统的硬件框架,如何达到并提高仪器性能指标等,并从信号的强度和仪器噪声等方面,研究了信号的信噪比。然后介绍了瞬变电磁探测仪的各部分功能模块电路设计,包括信号采集部分、前置放大模块、信号调理电路模块、供电部分、主控部分、键盘部分、显示部分、数据存储传输部分等。此外还介绍了数据处理的方法,如瞬态叠加、抽道算法等。同时对瞬变电磁探测仪的基本功能和工作过程进行了详细的介绍。论文最后给出了瞬变电磁探测仪的测量结果,其中包括仪器的一些性能测试和功能测试结果。性能测试包括发射电流大小、发射电流关断时间大小、最大不失真输入信号、接收信号动态范围等测量。功能测试结果表明,仪器实现了十五路信号的同时实时采集、测量结果显示等基本功能。本文的测量模式采用移动模式测量和定点模式测量。更多还原

【Abstract】 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.更多还原