RESEARCH ON BOUNDARY PROCESS TECHNIQUE IN HILBERT-HUANG TRANSFORM

The Hilbert-Huang transform (HHT) consists of two steps:empirical mode decomposition (EMD) and Hilbert transform. The end effects occurred both in the two steps. Analysis and research on the root cause and process techniques of boundary problem are given,wave characteristic matching extending method proposed to eliminate end effects both in EMD and Hilbert transform. Before the signal is decomposed by EMD,a series data are connected to the signal smoothly by proposed method. The data are derived from the original signal,so the extended wave have same characteristic with the original signal. When HHT process finished,abandon the data in extend position,thus end effects of HHT can be overcame. Only once extension needed in the whole process. The analysis results from the simulation and experiment signal demonstrate that the boundary problems can be resolve effectively.