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用b-splines变换的方法实现分数延迟滤波器matlab仿真程序

tau=0.3;
h1=[1 -3 3 -1]*(tau)^3/6;
h2=[0 1 -2 1]*(tau)^2/2;
h3=[0 1 0 -1]*(tau)/2;
h4=[0 1 4 1]/6;
hs=h1+h2+h3+h4;
x=conv(hs,x);
h=[1 4 1 ];
r=roots(h);
c=r(1);
a=[0 -1/c];
b=[1 -1/c];
d=[1 -r(2)];
[H1,w] = freqz(a,b);
[H2,w] = freqz(1,d);
m1=abs(H1);
m1=20*log10(m1);
figure(1);
plot(w/pi,m1);
figure(2);
m2=abs(H2);
m2=20*log10(m2);
plot(w/pi,m2);