daizu.m

数字信号处理 各种滤波器的设计

%带阻(haxes1,haxes2);
function []=gaotong(haxes1,haxes2)
haxes1=axes('position',[0.20,0.10,0.65,0.40]);
haxes2=axes('position',[0.20,0.55,0.65,0.40]);
fp=1,fs=2,ap=1;
fc=fp*(10^(0.1*ap)-1)^(-0.1);
[B1,A1]=butter(5,fc,'s');
[hf1,f1]=freqs(B1,A1,1024);
i=1;
while f1(i)<1
    h1(i)=hf1(i);
    fg1(i)=f1(i);
    i=i+1;
end
j=i-1;
while (f1(i)>=1)&&(f1(i)<2)
    h2(i-j)=hf1(i);
    fg2(i-j)=f1(i);
    i=i+1;
end
k=i-1;
while (f1(i)>=2)&&(f1(i)<3)
    h3(i-k)=hf1(i);
    fg3(i-k)=f1(i);
    i=i+1;
end

[B4,A4]=butter(5,[1,2],'stop','s');
[hf4,f4]=freqs(B4,A4,1024);
i=1;
while f4(i)<1
    a1(i)=hf4(i);
    b1(i)=f4(i);
    i=i+1;
end
j=i-1;
while (f4(i)>=1)&&(f4(i)<2)
    a2(i-j)=hf4(i);
    b2(i-j)=f4(i);
    i=i+1;
end
k=i-1;
while (f4(i)>=2)&&(f4(i)<3)
    a3(i-k)=hf4(i);
    b3(i-k)=f4(i);
    i=i+1;
end

axes(haxes2);
plot(fg1,abs(h1),'r');
axis([0.1,3,0,1.2]);
hold on;
%title('低通滤波特性');

axes(haxes1);
plot(b1,abs(a1),'r');
axis([0,3,0,1.2]);
hold on;
%title('带阻滤波特性');

pause(1);

axes(haxes2);
plot(fg2,abs(h2),'k');
axis([0.1,3,0,1.2]);
hold on;
%title('低通滤波特性');
axes(haxes1);
plot(b2,abs(a2),'k');
axis([0.1,3,0,1.2]);
hold on;
%title('带阻滤波特性');
pause(1)
axes(haxes2);
plot(fg3,abs(h3));
axis([0.1,3,0,1.2]);
hold on;
%title('低通滤波特性');
axes(haxes1);
plot(b3,abs(a3));
axis([0.1,3,0,1.2]);
hold on;
%title('带阻滤波特性');