【摘要】 针对基于Hilbert变换的零相位低通滤波器数值计算中,时域离散化带来的频域周期化影响了其低通特性的问题,提出了相应的改进方法。通过证明Hilbert低通滤波器时域解析表达式的频率响应特性,指出离散Hilbert低通滤波器的频响特性混叠了π两侧倒相的频率成分,并根据频响特性图的特征采用两级滤波结构对数值计算方法做出了改进。理论证明了改进后的滤波器能数值实现零相位低通滤波,并通过调幅信号以及调幅-调频信号的仿真算例进行了验证。应变实测信号处理实例表明,改进后滤波器能剔除动应变信号中低频的温度效应成分的影响,适合非平稳信号分析的预处理。更多还原

【Abstract】 A new method is proposed to improve the low-pass characteristics of the zero-phase Hilbert lowpass filter affected by periodic repetition of the frequency spectrum caused by time discretization changes in numerical calculations.The frequency response characteristic of the time domain analytical expression of the filter was demonstrated to prove that,in the numerical calculation,Hilbert low-pass filter frequency response characteristic retained phase inversion components on both sides ofπ.Then,the numerical calculation method was improved using a two-stage filter according to the pattern of frequency response characteristic graph,and the zero-phase low pass could theoretically be achieved.The amplitude modulation and amplitude modulation-frequency modulation simulation verified the characteristics of the proposed filter.Finally,the improved filter was applied on dynamic stain data of a field test to eliminate the temperature influence of low frequencies.The results showed that it was suitable for nonstationary signal preprocessing.更多还原