基于时频脊线旋转匹配的多普勒矫正方法研究

Doppler distortion correction method based on rotation matching of time-frequency ridge lines

多普勒效应使信号产生畸变,增加了道旁高速列车声学故障诊断的难度。时域重采样是一种有效的多普勒畸变矫正方法,该方法需要对时间中心有一个准确估计。在深入分析多普勒畸变信号瞬时频率变化特征的基础上,提出一种新的多普勒畸变校正方法。用时频融合技术提高时频图的分辨率,对时频脊线旋转匹配以获得时间中心,从而求得重采样序列用以校正多普勒畸变。仿真信号和实验信号分析结果表明,该方法能有效实现多普勒矫正,在道旁声学故障诊断中有一定的可行性。

Doppler effect causes acoustic signal distortion to increase the difficulty of wayside acoustic fault diagnosis of high-speed trains. Time-domain resampling is an effective Doppler distortion correction method requiring an accurate estimation of the time center. Based on deeply analyzing variation features of instantaneous frequencies of Doppler distortion signals,a new Doppler distortion correction method was proposed. Firstly,the time-frequency fusion technique was applied to improve the resolution of time-frequency figures. Then time-frequency ridge lines were rotated and matched with the original ones to achieve the time center. Finally,the resampling sequence was utilized to correct Doppler distortion. Simulations and tests demonstrated that the proposed method can be used to effectively realize Doppler distortion correction and has a certain feasibility for the wayside acoustic fault diagnosis.