摘要
传统的测量电路无法解决诸如海底大地电磁场这样微弱地学信号的检测问题。近几年诞生了一种称之为ΔΣ的电路理论以及相应的硬件芯片 ,给微伏级的弱信号检测开辟一条新的技术路径。文章介绍与地学探测有关的一种ΔΣ电路类型 ,该类型以低频段微弱信号为检测对象。采用系统理论和电路分析方法对ΔΣ原理作了较深入的讨论 ,阐明这种电路技术对提高微弱信号观测的分辨率是有效的。结合海底大地电磁探测中的信号采集问题 ,介绍了在仪器中把多路的被测模拟量变为数字量的技术过程。经对实际采集的海底信息的频谱曲线进行分析 ,证实所采用的ΔΣ技术以及多路信号采集的电路方案是合理的。
Traditional measuring circuit can't be used to detect the faint geosciences signal such as seafloor magnetotelluric signal. The circuit theory named Δ-Σ and its hardware chips have been developed in recent years, which has given a new way to detect the signal in the level of microvolt. In this paper, a Δ-Σ circuit is introduced which relates to geoscience detecting and is used to detect faint signal. The theory of Δ-Σ is discussed profoundly by using system theory and circuit analysis methods. It is explained that the resolution of detecting faint signal can be improved by using the circuit. The conversion from several channels of analog signals to the digital signals is introduced with the signal acquisition in the magnetotelluric detecting. It has been testified that the Δ-Σ techniques and the schemes of acquisition of several channels of signal are rational by analyzing the frequency response graph of the data acquired on the seafloor.
出处
《地学前缘》
EI
CAS
CSCD
2002年第4期417-421,共5页
Earth Science Frontiers
基金
国家"8 63"计划研究课题 (82 0 0 3 0 4)。
关键词
大地电磁
海洋探测
过抽样采集
系统分析
magnetotelluric
marine detecting
oversampling acquisition
system analysis
