Decomposition and reconstruction for non-stationary vibration signal of small engine

According to vibration signal of a small engine is non-stationary It extract the intrinsic mode function (IMF) of the signal through empirical mode decomposition (EMD).In order to overcome the mode mixing that happens in EMD, an improved EMD- ensemble empirical mode decomposition EEMD has been introduced. This dissertation analyses the reason of mixing and some solution at present, detailed introduces the basic principle, characteristics and related algorithm of EMD and EEMD. EEMD de-noising method was applied to analyze the vibration signals. With the simulation results of vibration signal, it points out that EEMD can solve the mode mixing, and at the same time reserve the adaptability of the EMD, it has no limits to the types of signals.