抖晃初相在振动频响估计误差中的作用

Effect of Initial Phase on Estimation Error of Frequency Response Analysis of Wow and Flutter

讨论抖晃初相在振动脉冲频响估计误差中的作用。在傅里叶分析的基础上,给出含抖晃初相的振动幅频、相频估计误差的数学表达,用仿真手段直观地展示二维和三维频响估计误差分布。由分析和仿真结果表明,抖晃初相对振动频响估计误差作用非常严重,除了周期特性以外,误差局部呈现极值、分布不对称以及误差整体有趋势项,这些特性使估计误差分布变得复杂化,造成后续的振动信号处理如模态参数识别丧失精度。因此,该问题的研究对信号处理有一定的理论和实际应用价值。

Based on the Fourier analysis,the estimation errors of frequency characteristic was given by a mathematical expression,and the estimation error distributions of the two and the three dimensional frequency responses were demonstrated by a simulation method. The results show that the effect of the initial phase on the estimation error of the frequency characteristic is remarkable. Besides of the estimation error with periodicity,it has other special properties,such as the local extremum,asymmetry contribution,as well as the whole tendency of distribution,which make the error distribution much more complicated,and result in low accuracy of further signal processing,for instance,the parameter recognition losing estimation accuracy in vibration modal analysis. Therefore,the given investigation result is valuable for signal processing in theory and in engineering practice.