In view of complex and changeable background noise in coal mines exploitation

the key question is how to extract the effective AE signal.Improved AE sensor dual-wavelength stability technology and the wavelet multi-criterion analysis have great time-frequency-domain and localization characteristic

by carrying on time-frequency analysis procession to the wavelet coefficient

and partial noise is eliminated by wavelet restructing and the threshold technology

denoising procession is carried on to restructing signal

the effective AE signal is extracted.The result indicates that this method is used to enhance signal-to-noise ratio of the AE signal effectively and achieve the denoising aim.