Filtering technique for mining vibration signals and its affection on the signals’ time-frequency characteristics

Mining vibration plays an important role in research such as microseismic characteristics,vibration attenua- tions,and the hazard evaluation of vibration. However,the baseline drift caused by low frequencies and the 50 Hz pow- er line interferences often reduces the quality of the measured signals,especially when the signals have a low energy. To address this issue,a finite impulse response (FIR) filter,with linear-phase and the ability of self-adaption,is sug- gested for the vibration signals measured in mine as a supplementary preprocessor. First,based on the linear-phase FIR theory,the automatic design procedure of the Chebyshev optimal approximation method is given. Then,according to the practical requirements in mine,a self-adaption step is added to the automatic design procedure,in order to adapt the scaling near 50 Hz based on each signal’s characteristics automatically. Finally,the differences of the PPV,the domi- nant frequency,the Fourier spectrum,the wavelet coefficient spectrum and the absolute accelerate response spectrum between the signals before and after filtered are assessed. The result shows that the proposed filter can filter the inter- ference signal efficiently,and retain the time-frequency characteristics as well as possible.