Hilbert-Huang变换与大地电磁信号的时频分析

Hilbert-Huang transform and time frequency analysis of magnetotelluric signal

将Hilbert-Huang变换引入大地电磁信号的时频分析中,介绍HHT(Hilbert-Huang transform)时频分析原理及方法,给出仿真信号的经验模态分解及其时频分布,并对实测大地电磁信号进行HHT时频处理与剖析。研究结果表明:Hilbert能量谱随时频的具体分布具有很强的非稳态动态变换时频刻画能力;时频谱的时间、频率分辨率不受Heisenberg测不准原理的限制,且其时间、频率分辨率都很高,有很好的时频聚集性;HHT方法能用于描述大地电磁信号的非线性时变特征,是大地电磁信号时频分析的有效工具。

Hilbert-Huang transform was proposed as a method of time frequency analysis in magnetotelluric（MT）signals processing.Firstly,the time frequency analysis method of Hilbert-Huang transform and conception of transient frequency were introduced,and the empirical mode decomposition and time frequency distribution of a simulative signal was carried out.Then the actual MT data series were analyzed and processed based on Hilbert-Huang transform（HHT）spectrum.The results show that Hilbert energy spectrum can clearly show the energy distribution with time and frequency in detail and has strong ability to analyze non-stationary signal.In HHT spectrum,time and frequency resolving power is strong and not restricted by Heisenberg principle.Hilbert-Huang transform can be used to precisely describe the nonlinear and non-stationary characteristics of MT signals,and it is an effective tool of time frequency analysis in MT signals processing.