Abstract: An energy operator demodulating approach based on EMD (Empirical mode decomposition) is proposed to extract the frequencies and amplitudes of the multi-component AM- FM signals. Furthermore, the proposed approach is applied to mechanical diagnosis. In this approach, EMD method is used to decompose a multi-component AM-FM signal into a number of intrinsic mode functions (IMF) firstly; then, the energy operator demodulating is applied to each IMF and the amplitudes and frequencies of a multi-component AM-FM signal are extracted. The proposed approach is applied to mechanical fault diagnosis. The analysis results show that the energy operator demodulating approach based on EMD can extract the characteristics of mechanical fault vibration signals efficiently.

Key words: AM-FM signals, EMD, Energy operator demodulating, Mechanical fault diagnosis