高铁振动信号的频率提取与定频降噪

Frequency extraction and constant frequency noise reduction of high speed railway vibration signal

为探索高铁振动信号的特征,并且对其噪声进行防治,减少振动对周边环境、设备和精密仪器的影响,在河北某高架桥附近利用振动采集设备采集列车经过时产生的信号。结合同步压缩小波变换技术,在多组信号的对比下,提取出高铁振动信号的主要频率和能量集中点;同时对传统的滤波型最小均方算法进行了定频性和实时性优化,提高降噪速率和针对性,结合主动噪声控制技术对上述提取的噪声进行主动降噪处理,结果表明,高铁振动主要频率为10 Hz和20 Hz以及少量低频信号,振动有明显的主次峰能量聚集。传统的降噪算法对于高铁振动这种短时、定频信号降噪的实时性和定频性较弱,在对其进行优化后,从仿真结果看出,优化后的主动噪声控制技术对特定频点噪声的实时防治有较好的效果。

In order to explore the characteristics of high speed railway vibration signal,prevent and control its noise,and reduce the impact of vibration on the surrounding environment,equipment and precision instruments,vibration acquisition equipment is used near a viaduct in Hebei to collect the signal generated when the train passes by.Combined with synchronous compression wavelet transform technology,the main frequency and energy concentration points of high speed railway vibration signals are extracted by comparing multiple groups of signals.At the same time,the traditional filtered least mean square algorithm is optimized in fixed frequency and real time to improve the noise reduction rate and pertinence.Combined with active noise control technology,the noise extracted above is actively reduced.The results show that the main frequency of high speed railway vibration is 10 Hz and 20 Hz,and a small number of low⁃frequency signals.The vibration has obvious primary and secondary peak energy accumulation.The traditional noise reduction algorithm has a weak real⁃time and fixed frequency performance for high speed railway vibration,which is a short⁃time and fixed frequency signal noise reduction.After optimization,from the simulation results,the optimized active noise control technology has a good effect on the real⁃time prevention of noise at specific frequency points.