基于小波分析的FIR滤波器改进方法

用窗函数法设计FIR滤波器,由于非一致收敛而产生振荡,从而影响了滤波器的精度,而提高精度是以增加计算量为代价的,对于实时系统是很不利的。文章以小波低通滤波器H的逆Fourier变换所得的序列同滤波器脉冲序列相乘,相当于小波对滤波器的频域信号进行滤波,在滤波器阶数不高的情况下,能起到平滑滤波器通带频谱,抑制高频成分,达到减小误差及增强抗混叠能力的作用。

Improvement of FIR filters based on wavelet analysis

The design of finite impulse reponse(FIR) filters which is based on the window function may produce oscillation for the non-uniform convergence of the filter,which affects the precision of the filter,but improvement on the precision need increase the calculation amount,which is unfavorable to the real-time system.In the paper,the sequence of inverse Fourier transformation of wavelet low-pass filters is multiplied by the filter pulse sequence,thus filtering the frequency-domain signal using wavelet filters.This method can be used to smooth the filter's transmission band and reject high frequency components,thus reducing the error and improving the anti-aliasing capacity of low-order filters.