untitled12.m

这个是我数字信号处理这门课的课程设计,文件包括用matlab编写的代码和设计报告.这个设计包括卷积演示程序、采样定理演示程序、模拟滤波器设计演示程序、设计切比雪夫I型低通滤波器、切比雪夫I型低通滤波器

Ws=0.6*pi;Wp=0.4*pi;ap=0.5;as=50;T=2;
Us=2*tan(0.5*Ws)/T;
Up=2*tan(0.5*Wp)/T;
Kp=1;Ksp=Us/Up;
ksp=sqrt((10.^(0.1*ap)-1)/(10.^(0.1*as)-1));
N=-log10(ksp)/log10(Ksp);
N=fix(N)+1;
Uc=Up/((10.^0.05-1).^(1/2*N));
Uc=Up*(10^(0.1*ap)-1)^(-1/(2*N));
w=linspace(0,1,100)*pi;
for i=0:1:N-1;
sk=Uc*exp(j*pi*(0.5+(2*k+1)/(2*N)));
Ha=Uc.^N;
s=2*(1-exp(-jWT))/(T*(1+exp(-jWT)));
Ha=Ha/(s-sk(n+1))
end
plot(s,Ha)
[n,Wn]= buttord(Wp,Ws,ap,as);
[b,a]=butter(n,Wn,/ftype/);
w=linspace(0,1,100)*pi;


H=freqs(b,a,w);
magH=abs(H);
m=20*log10(magH);
http://zhidao.baidu.com/question/9242846.html


Ws=0.6*pi;Wp=0.4*pi;ap=0.5;as=50;T=2;
Us=2*tan(0.5*Ws)/T;
Up=2*tan(0.5*Wp)/T;
Kp=1;Ksp=Us/Up;
ksp=sqrt((10^(0.1*ap)-1)/(10^(0.1*as)-1));
N=-log10(ksp)/log10(Ksp);
N=fix(N)+1;
Uc=Up*(10^(0.1*ap)-1)^(-1/(2*N));
W=linspace(0,1,100)*pi;
s=(2*(1-exp(-j.*W)))./(T*(1+exp(-j.*W)));
Ha=Uc^N;
for i=0:1:N-1;
sk(i+1)=Uc*exp(j*pi*(0.5+(2*i+1)./(2*N)));
Ha=Ha./(s-sk(i+1));
end
H=abs(Ha);
title('幅度特性');
subplot(2,1,1)
plot(W,H)
xlabel('w/rad');ylabel('幅度|H(jw)|');
axis([0,pi,0,1.1])
grid on
m=20*log10(H);
subplot(2,1,2)
plot(W,m)
axis([1,2,-80,0])
xlabel('w/rad');ylabel('增益20log|H(esp(jw))| (dB)');
grid on
figure
y=ifft(Ha);
t=0:T:99*T;
plot(t,abs(y))
xlabel('t');ylabel('绝对值|y|');





Ws=0.6*pi;Wp=0.4*pi;ap=0.5;as=50;T=2;
Us=2*tan(0.5*Ws)/T;
Up=2*tan(0.5*Wp)/T;
Kp=1;Ksp=Us/Up;
ksp=sqrt((10^(0.1*ap)-1)/(10^(0.1*as)-1));
N=-log10(ksp)/log10(Ksp);
N=fix(N)+1;
Uc=Up*(10^(0.1*ap)-1)^(-1/(2*N));
W=linspace(0,1,100)*pi;

s=(2*(1-exp(-j.*W)))./(T*(1+exp(-j.*W)));
Ha=Uc^N;
for i=0:1:N-1;
sk(i+1)=Uc*exp(j*pi*(0.5+(2*i+1)./(2*N)));end

Ha=Ha./((s-sk(1)).*(s-sk(2)).*(s-sk(3)).*(s-sk(4)).*(s-sk(5)).*(s-sk(6)).*(s-sk(7)).*(s-sk(8)).*(s-sk(9)).*(s-sk(10)).*(s-sk(11)));
Ha=abs(Ha);
plot(W,Ha)