瞬变电磁专用信号源的研制

发布时间：2018-03-17 00:16

本文选题：瞬变电磁　切入点：信号源　出处：《成都理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：瞬变电磁法,又称为时间域电磁法,是一种建立在电磁感应基础上的时间域人工源电磁探测方法,主要应用于地质探测领域。其中瞬变电磁接收机作为数据采集和存储的主要途径,其性能直接影响到后期的数据处理和解释。因此,人们对瞬变电磁接收机的性能提出了更高的要求。随着现代电子技术和计算机技术的不断发展,高分辨率、高灵敏度和高抗干扰度的瞬变电磁仪器成为研究人员研究的主要方向。而在仪器的研制过程中,每次实验都需要到野外进行测试,这耗费了大量的时间、人力和物力。如果能够模拟野外实测信号就能在室内进行仪器的测试,这不仅能降低实验成本,改进仪器,而且还能在野外作业前对仪器进行标定。市场上现有的通用信号发生器,很难模拟出适用于瞬变电磁仪器的原始信号波形,因此,本文设计了一种为实验室内瞬变电磁仪器的研发提供参考信号的专用信号源。本文依托于国土资源部公益性项目“基于无人机的半航空瞬变电磁勘查技术研究”(项目编号:201311037),论文的主要内容如下:第1章首先介绍了瞬变电磁法的研究背景和瞬变电磁专用信号源的研制意义;然后论述了信号发生器的发展历史和技术现状;最后根据本课题的要求,提出了本系统的设计指标。第2章从理论上分析了瞬变电磁信号产生的原理及其特征,进而建立了瞬变电磁信号的仿真模型;分析了影响瞬变电磁信号的主要噪声及其特点,基于对野外实测数据的分析,研究了油动无人直升机对瞬变电磁接收机的影响,并建立相应的matlab仿真模型,为瞬变电磁专用信号源的研制奠定了理论基础。第3章介绍了DDS原理,通过方案论证,提出了基于SOPC的系统设计方案。详细阐述了相位累加器模块和SRAM控制切换模块的设计,采用高速的数模转换芯片ISL5961和高压摆率的运放芯片THS4271设计了数模转换电路和低通滤波电路并介绍了电源部分的设计。第4章采用图形化编程方法的Lab VIEW设计了上位机软件,对波形数据产生、显示和参数处理模块的功能和设计方法进行了介绍。第5章首先提出了系统的测试方案。采用自底向上的原则,对电源的纹波进行测试,并对FPGA内部模块进行功能仿真测试。最后对整个系统进行了总体测试,测试结果表明基本实现了预期的功能。通过这些研究,有利于减少瞬变电磁接收仪器研制过程中的测试成本,对于提高其性能指标和仪器标定具有重要意义。
[Abstract]:Transient electromagnetic method, also known as time-domain electromagnetic method, is a time-domain artificial source electromagnetic detection method based on electromagnetic induction. The transient electromagnetic receiver is the main way of data acquisition and storage, and its performance directly affects the later data processing and interpretation. People demand higher performance of transient electromagnetic receiver. With the development of modern electronic technology and computer technology, high resolution, Transient electromagnetic instruments with high sensitivity and high anti-jamming degree have become the main research direction of researchers. However, in the development of the instrument, each experiment needs to be tested in the field, which takes a lot of time. Manpower and material resources. If you can simulate the field measured signals, you can test the instruments indoors, which can not only reduce the cost of the experiment, but also improve the instruments. Moreover, the instrument can be calibrated before the field operation. It is very difficult to simulate the original signal waveform suitable for transient electromagnetic instrument in the existing general signal generator on the market, so, In this paper, a special signal source is designed to provide reference signal for the research and development of laboratory transient electromagnetic instruments. This paper is based on the public welfare project of Ministry of Land and Resources, "Research on Semi-Aeronautical transient electromagnetic Prospecting Technology based on UAV" (. Item number: 201311037. the main contents of this paper are as follows: in Chapter 1, the research background of transient electromagnetic method and the significance of developing special signal source for transient electromagnetic are introduced. At last, according to the request of this subject, the design index of the system is put forward. In chapter 2, the principle and characteristics of transient electromagnetic signal generation are analyzed theoretically. Then, the simulation model of transient electromagnetic signal is established, and the main noise and its characteristics that affect the transient electromagnetic signal are analyzed. Based on the analysis of field measured data, the influence of oil-operated unmanned helicopter on the transient electromagnetic receiver is studied. The corresponding matlab simulation model is established, which lays a theoretical foundation for the development of special transient electromagnetic signal source. Chapter 3 introduces the principle of DDS and demonstrates the scheme. The system design scheme based on SOPC is proposed, and the design of phase accumulator module and SRAM control switch module are described in detail. The digital-analog conversion circuit and low-pass filter circuit are designed by using high-speed digital-analog converter chip ISL5961 and high-voltage swing rate operational amplifier chip THS4271, and the design of power supply part is introduced. In chapter 4, the upper computer software is designed by using graphical Lab VIEW. The function and design method of waveform data generation, display and parameter processing module are introduced. In chapter 5, the test scheme of the system is put forward firstly, and the ripple of power supply is tested by bottom-up principle. Finally, the whole system is tested, and the test results show that the expected function is basically realized. It is beneficial to reduce the testing cost in the development of transient electromagnetic receiver, and it is of great significance to improve its performance index and instrument calibration.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.325

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