用改进的窗函数设计FIR数字滤波器

Research on FIR Digital Filter Design Using an Improved Window Function

窗函数设计FIR数字滤波器已多年,近年来,用优化技术设计数字滤波器十分流行,论文提出了一种新方法对窗函数进行改进,这种窗函数不同于以往的Hann窗、Hamming窗、Blackman窗,它先将余弦序列线性组合为窗函数,然后根据FIR数字滤波器的特性对数字滤波器的幅度条件进行线性规划。并且给出了改进窗函数的算法。最后,用该方法设计出了FIR数字滤波器的仿真实例,并与用Hamming窗、Blackman窗方法设计的FIR滤波器进行对比,仿真结果表明用该方法设计的滤波器满足设计规格。

Window function has been used to design a linear phase digital filer for long times,but the use of optimization techniques for designing digital filter has become widespread in recent year.A new method has been proposed to improve FIR window function in this paper.The window function that combines with cosine sequences in linear is different from previous Hann,Hamming and Blackman window function.The paper also proposes linear programming to optimize characterization of FIR digital filter according to its magnitude condition,and gives out the algorithm to design digital filter using the improved window function.Finally,we have designed FIR filter using new window for simulation and compared with the filter designed by Hamming window,Blackman window function.The simulation results show that filters designed using this method to meet the design specifications.