时域同步平均的相位误差累积效应研究

Research on phase error accumulation effect of time synchronous averaging

时域同步平均是提高振动信号信噪比的常用方法,由于估计误差的存在性,相位误差累积效应是基于周期的时域同步平均方法的固有现象。对相位误差累积效应的产生机理进行了深入分析,表明这一效应是由取整运算误差和频率估计误差引起的。为统一分析这两种误差的影响,定义了相位误差累积因子,用其定量分析了相位误差累积效应的产生机理。为评估相位误差累积效应对时域同步平均效果的影响,系统分析了相位误差累积因子、信号分量阶次和平均段数等主要分析参数对时域同步平均信号幅值的影响规律。研究表明,一定范围内这几个参数的增大都会增强相位误差累积效应导致的时域同步平均信号幅值的衰减。因此,需要根据相位误差累积因子和信号分量阶次的范围慎重选择平均段数。

Time Synchronous Averaging （TSA） is a useful technique to enhance signal-noise-ratio of vibration signal. As the estimation error is inevitable, Phase Error Accumulation Effect is inherent for TSA. After analyzing the process procedure of TSA, it is shown that Phase Error Accumulation Effect is aroused by round estimation error and frequency estimation error. To consolidate the effect of these two error factor, Phase Error Accumulation Factor is defined. On the basis of this factor, the generating rule of Phase Error Accumulation Effect is studied quantificationally. To estimation the affecting rule of Phase Error Accumulation Effect on TSA, the influence rule is studied thoroughly for different TSA parameters including Phase Error Accumulation Factor, component order and averaging number. It is shown that the increase of these parameters will enhance the attenuation of TSA induced by Phase Error Accumulation Effect. So it is suggested that averaging number should be choosed cautiously according to the range of Phase Error Accumulation Factor and component order.