伪随机编码在高密度电法中的实现

发布时间：2018-03-23 06:04

本文选题：密度电法　切入点：直流电法　出处：《吉林大学》2015年硕士论文　论文类型：学位论文

【摘要】：伪随机编码是一种按照事先制定好的伪随机函数，根据作业需要生成相应的伪随机信号的编码方式，产生的伪随机信号具备多阶主频，伪随机信号一次供电多阶主频的特点可以帮助高密度电法克服极化效应带来的影响，由这些具备多阶主频的信号可以计算出同一频率的相对准确的视电阻率、百分频散率等地探参数，从而在推算地址体结构以及地表以下矿体的种类和分布情况时起到极大的作用。目前国内外的高密度电法设备种类繁多，但是总的来看发射技术非常相似，多采用占空比为1：1的方波信号。直流电法无法克服接地电极极化产生的极化效应所带来的影响，无法得到相对准确的极化率，常规的直流高密度电法为了得到相对准确的极化率，一般都配备两套电极系统，即一套发射电极和一套测量电极，成本高、操作复杂、仪器笨重、野外实验不方便、故障率高等等缺点使得直流高密度电法仪器使用起来有诸多不便。本文对伪随机编码如何在高密度电法测量的实现进行了详尽研究，主要包括人机交互界面设计部分，伪随机信号生成部分，数据处理及计算相关参数部分，电阻试验及阻容试验分析部分，结果验证部分。以上几个部分为本文主要研究内容。伪随机信号生成部分。伪随机信号生成部分介绍了伪随机编码的编译规则及其生成原理，三阶、五阶、七阶伪随机信号的生成及其傅氏频谱，推算发射机使用的伪随机信号三个部分，伪随机编码的编译规则是取自何继善院士的在《广域电磁法和伪随机信号电法》中提到的伪随机函数，其生成原理类似于二进制数的某种加法规则，发射机使用的伪随机信号是由-1、0、1三个数字码组成的信号。上位机部分。上位机是用C++程序语言设计出来的，使得操作者通过操作微型计算机与高密度电法仪进行通信的可执行程序，，该程序由Microsoft Visual Studio2005设计平台开发，可兼容xp、vista、win7等运行环境，该程序包括参数设置部分，示波器显示部分，仪器返回信息显示部分，以及操作者操作部分。上位机可命令仪器实现编号操作、不同方式的跑极操作，可调整示波器显示时横轴和纵轴的长短，可自由设置数据存储目录，可添加自定义跑极方式等等。数据处理及计算相关的地电参数。该部分是将测量数据从上位机程序保存的二进制文件中提取出来，进行一系列的处理之后，将单位换算成真值，然后算出电阻率，根据得到的相应阶次的主频，推算相应阶次的百分频散率。电阻串试验及阻容试验分析部分。经过一系列理论分析之后，根据电阻串实验得到的数据对比理论值，得出将伪随机编码应用在高密度电法中，能够完成对百分频散率的测量的结论。
[Abstract]:Pseudorandom coding is a coding method that generates corresponding pseudorandom signals according to the need of operation according to the predefined pseudorandom function. The generated pseudorandom signals have multi-order main frequency. The characteristic of pseudo-random signal supplying multi-order main frequency at one time can help the high-density electric method to overcome the influence of polarization effect. The relatively accurate apparent resistivity of the same frequency can be calculated from these signals with multi-order main frequency. The parameters such as dispersion rate play a great role in calculating the structure of the address body and the types and distribution of orebodies below the surface of the earth's surface. At present, there are many kinds of high-density electrical equipment at home and abroad, but generally speaking, the emission technology is very similar, and the square wave signal with duty cycle of 1:1 is mostly used. Direct current method can not overcome the effect of polarization effect caused by the polarization of grounding electrode. In order to get a relatively accurate polarizability, the conventional DC high-density electric method is usually equipped with two sets of electrode systems, one set of emission electrode and one set of measuring electrode, which have high cost, complex operation and heavy instrument. The disadvantages of inconvenient field experiments and high failure rate make it inconvenient to use DC high density electrical instruments. In this paper, the implementation of pseudorandom coding in high-density electrical measurement is studied in detail, including the design of human-computer interface, the generation of pseudo-random signals, the data processing and the calculation of related parameters. Resistance test and resistance and capacitance test analysis part, the result verification part, the above several parts are the main research content of this paper. The part of pseudorandom signal generation introduces the compiling rule and generating principle of pseudorandom coding, the generation of third, fifth and seventh order pseudorandom signal and its Fourier spectrum. Three parts of the pseudorandom signal used in the reckoning transmitter are derived from the pseudorandom function mentioned in academician He Jishan's wide area electromagnetic method and pseudorandom signal Electric method. Its generating principle is similar to some addition rule of binary number. The pseudorandom signal used in transmitter is a signal composed of three digital codes. The upper computer part. The upper computer is designed with C program language, which makes the operator communicate with the high density electric instrument by operating the microcomputer. The program is developed by the Microsoft Visual Studio2005 design platform. The program includes parameter setting part, oscilloscope display part, instrument return information display part, and operator operation part. Adjustable oscilloscope display when horizontal axis and longitudinal axis length, free to set data storage directory, can add custom pole run and so on. Data processing and calculation of related geoelectric parameters. This part is to extract the measured data from the binary files saved by the upper computer program, after a series of processing, the unit is converted into the true value, and then the resistivity is calculated. According to the main frequency of the corresponding order, the dispersion rate of the corresponding order is calculated. After a series of theoretical analysis, the pseudorandom coding is applied to high density electrical method according to the theoretical value of the data obtained from the resistance string test. Can complete the measurement of the dispersion rate of 100.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.3

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