怎么制作notch filter

1、怎具干扰信号的频率计算出角速度w=2π*f

2、求出零点和极点

3、求出频率相应方程H(w)

4、在Matlab里可以看到结果。参考的代码

5、clear all;clc;close all;z1 = exp(j*0.2513);z2 = exp(-j*0.2513);z3 = exp(j*0.5027);z4 = exp(-j*0.5027);p1 = 0.999*exp(j*0.2513)p2 = 0.999*exp(-j*0.2513);p3 = 0.999*exp(j*0.5027)p4 = 0.999*exp(-j*0.5027);a = poly( [p1,p2,p3,p4] )b = poly( [z1,z2,z3,z4] );G = polyval(a,1) / polyval(b,1);b=b*Gfvtool(b,a)w = linspace(-pi,pi,1000);H=G.*((exp(-j*w)-z1).*(exp(-j*w)-z2).*(exp(-j*w)-z3).*(exp(-j*w)-z4))./... ((exp(-j*w)-p1).*(exp(-j*w)-p2).*(exp(-j*w)-p3).*(exp(-j*w)-p4));figureplot(w,abs(H));grid;title('Frequency Response')xlabel('\omega')ylabel('|H(\omega)|')[x,fs]=wavread('xiaomifeng.wav')y = filter(b,a,x)figurespecgram([x;y],1000,5000)sound(y,Fs)