基于双重对称延拓的HHT端点效应抑制方法

经验模态分解( empirical mode decomposition，EMD)存在端点飞翼的固有问题，使信号两端出现扭曲失真。为抑制EMD端点效应，文章提出双重对称延拓法，以端部数据对称延拓作为首次延拓，以极值点对称延拓作为二次延拓，该方法可同时实现EMD分解和Hilbert变换两阶段端点效应的抑制。仿真信号和地震响应的工程算例通过IMF分量对比、瞬时频率对比，以及整体正交性、相关系数等指标的对比，验证了该方法具有良好的端点效应抑制效果,同时还能改善IMF分量之间的正交性，并节约计算时间。

A dual symmetrical extension method for end effects reduction of Hilbert-Huang transform

End effects reduce the precision of empirical mode decomposition (EMD) greatly．A dual symmetrical extension method was proposed to decrease the end effects of EMD. Signal end data symmetrical extension was regarded as the first extension, whereas extreme symmetrical extension was regarded as the second extension. The proposed method can also decrease the end effects of Hilbert transform. The harmonic superimposed signal and absolute acceleration response were applied to test the performance of the proposed method. The results show that the proposed method can reduce the end effects of HHT and can improve its precision significantly.