Time-dependent power spectral density estimation of AE signals of rock based on wavelet transform

Understanding and cognition on characteristics of acoustic emission (AE) signals is the foundation and precondition of read comprehensively AE signals. Traditional Fourier amplitude spectrum and power spectral density(PSD) representations based on Fourier transform have limitations, that is, it loses any information related to time and is unable to completely reflect the non-stationary characteristics of AE signals essentially. In this paper, based on wavelet transform, the relationship between wavelet coefficient in every frequency bands and power spectral density is derived; PSD estimate method and time-dependent PSD estimate method based on wavelet transform are also presented in this paper. The feasibility of the presented method is illustrated by AE Signal of rock processing and analysis.