Experimental Research on Noise Source Spectrogram of a High-speed Train’s Pantograph

Abstract

Using acoustic phased array technique to take an experiment research on noise source spectrogram of a high-speed train’s Pantograph. The post-processing algorithm Non Negative Least Squares method (NNLS) is applied to deal with the initial source image obtained by traditional beamforming algorithm Day-and-Sum (DAS), and the number of iterations is chosen as 300 steps. The results of experiment show that noise of the pantograph raised is obviously larger than noise of the pantograph dropped, and the SIL of the pantograph “knuckle†facing backward is greater about 1dBA than the SIL of pantograph “knuckle†faced forward. Last, the noise source spectrogram of the pantograph raised is fitted by quadratic polynomial. According to the spectral fitting, the peak frequency is around 1.4kHz which is greater than the spectrogram of experiment. Therefore the sound energy of pantograph is mainly concentrated in the high frequency region.