抽取滤波在海底大地电磁探测中的应用  

The application of decimation filter in marine bottom magnetotelluric exploration

作　　者：邓靖武[1] 邓明[1] 魏文博[1] 熊玉珍[1] 邓靖武 邓明[1] 魏文博[1] 熊玉珍[1] 邓靖武[1] 邓明[1] 魏文博[1] 熊玉珍[1] 邓靖武[1] 邓明[1] 魏文博[1] 熊玉珍[1] 

机构地区：[1]中国地质大学地球物理与信息技术学院,北京100083

出　　处：《吉林大学学报（地球科学版）》2004年第2期271-276,共6页Journal of Jilin University：Earth Science Edition

基　　金：国家"863"计划研究课题资助项目(820-03-04)(2002AA615020)

摘　　要：海底大地电磁仪使用了Δ-Σ调制技术来实现微伏级信号的采集。从抽样理论出发,讨论了针对Δ-Σ调制器输出的高频位流信号而进行的抽取滤波的原理及其构成,指出抽取滤波过程中必须使用多级抽取结构进行抽取和滤波,海底大地电磁仪器中使用的三级抽取滤波结构实现了数字抽取、抗混叠和滤除基带以外量化噪声的功能。同时也介绍了滤波模块的接口和海底大地电磁数据采集器中数字通道原理。结合海底大地电磁仪器的海上试验,通过分析采集的时间序列及其频谱曲线,说明海底大地电磁仪中使用的抽取滤波是合理、可行的。The technique of Δ-Σ modulator is used in the marine bottom magnetotelluric(MT) instruments to acquire microvolt-order signal. Based on sampling theory, the principle and composition of the decimation filter corresponding to the high frequency bitstream from the Δ-Σ modulator are discussed. It is then pointed out that the decimation filtering must be carried out by multi-order decimation structure. Three-order filter structure used in marine MT instruments has three functions including decimation, resisting of aliasing and filtering the noises out of baseband. The authors also introduce the interface of filtering model and the principle of digital channels in the instruments. It is shown that the decimation filters used in marine bottom MT instruments are reasonable and feasible on the analysis to the time signals from an experiment and their frequency responses.

关 键 词：大地电磁探测 抽取滤波 海洋探测 过抽样 

分 类 号：P714.8[天文地球—海洋科学]