信号FIR数字滤波后相位延迟的消除

Eleminate phase delay of FIR filtered signal

针对信号处理中采用FIR数字滤波器对信号进行滤波后将产生相位延迟的现象,从FIR数字滤波器的相位特性出发,分析并推导了产生这种延迟现象的原因,得到了FIR数字滤波器的阶数和相位延迟的关系。采用基于波形匹配的数据扩展的方法对原始的信号进行端点延拓,再对延拓后的信号进行FIR滤波,可以很好地消除这种相位延迟的现象。Matlab仿真结果证明运用该方法滤波后的信号相位与原始信号相位一致,相位延迟被消除了。通过对信号的Simulink仿真实验及分析,也证实该方法可以有效消除FIR数字滤波器产生的相位延迟。

Mainly focusing on the phenomenon that the phase will delay by using the FIR digital filter in signal processing, starting from the phase characteristic of the FIR digital filter, this paper analyzes and deduces the reasons of this phenomenon and obtains the relationships of the order and the phase delay. This paper adopts the method based on waveform matching to extend data of the original signal, and then filters the signal by FIR filtering. The Matlab simulation shows that the relationships between the order and the phase delay completely consist with the theoretical deduction. The phenomenon is eliminated completely. The results of Matlab simulation show that filtering the signal using the method proposed in this paper can completely eliminate the phase delay and obtain the wave phase consisting with the initial signal. Through analyzing the actual signal with simulink, the proposed method can effectively eliminate the phenomenon of phase delay caused by FIR digital filter.