直接消除电磁耦合的斩波去耦方法

应用激发极化法时经常遇到电磁耦合的干扰.基于耦合效应和激电效应在双频波测量波形上具有不同的表现形式，提出一种在野外采集激电数据时，直接剔除电磁耦合而又基本上不损失激电信息的“斩波”去耦方法.本文从“斩波去耦”的方法原理、斩波对正常双频波产生的畸变、以及存在EM和IP效应时的双频波斩波等方面进行了详细的推导和分析.数值计算结果表明，该方法去耦效果明显，可以在现场条件下直接去耦，值得在激发极化法中推广应用

A direct induced-polarization decoupling scheme by chop-wave

It is known that the electromagnetic coupling effect is a disturbance factor in induced-polarization measurements.Based on the different appearances of EM coupling effect and IP effect in measured dual-frequency waveform,a direct decoupling scheme by chop-wave is presented in this paper.The method is able to eliminate EM coupling effect directly during the field data acquisition,and it does not suffer loss of IP information by and large.This paper has mainly discussed several aspects,which include the fundamentals of chop-wave,the distortion of normal dual-frequency wave resulting from chopping wave,chopper of existing pure EM coupling effect and IP effect's loss due to chop-wave.The numerical results show that the scheme reduces and eliminates EM coupling effect markedly and can provide some parameter bases for the development and design on the correlative instrument.Thereby,it is worth generalizing the chop-wave for decoupling scheme in induced polarization method.