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实验内容
对于给定带频谱信号f(t),其频谱F（jΩ）=cosΩ （ -0.5π<Ω<0.5π）F（jΩ）=0 其它
1.汇出此信号的频谱图（Ω的取值：-0.5π<Ω<0.5π，精度取0.01rad）。
2.对此频域信号进行傅里叶反变换，得到相应的时域信号，绘出此信号的时域f(t) (t的取值：-20s<t<20s;精度取0.1s)
3.分别用3种不同的采集频率fs=0.2HZ,0.5HZ,1.0HZ,…
4.针对3中采样所得的矩形采样信号，用录波器H（jΩ）…
第1问
clc
clear all
hold off
x=[-0.5*pi:0.01:0.5*pi];
F=cos(x);
plot(x,F);
title('信号频谱图')
xlabel('j(Ω)');
ylabel('F(jΩ)')
第2问
clc
clear all
hold off
m=1;
for i=-20:0.1:20
ans(m)=fuliye2(i);
m=m+1;
end
plot([-20:0.1:20],ans);
------------------------------------------------
function[ans]=fuliye2(t)
w=-0.5*pi;
f=0;
while(w<=0.5*pi)
f=f+cos(w)*cos(w*t)*0.01;
w=w+0.01;
end
ans=f/(2*pi);
end
第3问
clc
clear all
hold off
inf=200;
f1=0.2;
f2=0.5;
f3=1.0;
fs=0;
%------------------------------------
figure(1);
m=1;
for i=-10:0.01:10
fs1(m)=fly3_2(i,f1,inf);
m=m+1;
end
title('f=0.2Hz')
hold on
plot([-10:0.01:10],fs1);
%------------------------------------
figure(2);
m=1;
for i=-10:0.01:10
fs2(m)=fly3_2(i,0.2,inf);
m=m+1;
end
title('f=0.5Hz')
hold on
plot([-10:0.01:10],fs2);
%------------------------------------
figure(3);
m=1;
for i=-10:0.01:10
fs3(m)=fly3_2(i,f3,inf);
m=m+1;
end
title('f=1.0Hz')
hold on
plot([-10:0.01:10],fs3);
-----------------------------------
function[ans]=fly3_1(x)
if (x>=-0.5*pi&&x<=0.5*pi)
ans=cos(x);
return
end
ans=0;
end
-----------------------------------
function[ans]=fly3_2(w,f,inf)
s=0;
for i=-inf:1:inf
s=s+f3_1(w-i*2*pi*f)*sa3(i*2*pi*f*0.01/2);
end
ans=s*0.01*f;
end
------------------------------------
function[ans]=sa3(x)
if (x==0)
ans=1;
return
end
ans=sin(x)/x;
end
第4问
clc
clear all
hold off
inf=200;
f1=0.2;
f2=0.5;
f3=1.0;
fs=[];
%-----------------------------------------------
figure(1);
m=1;
for i=-2:0.01:2
if(i>-0.5*pi&&i<0.5*pi)
fs1(m)=fly3_2(i,f1,inf);
m=m+1;
continue;
end
fs1(m)=0;
m=m+1;
end
title('f=0.2Hz')
hold on
plot([-2:0.01:2],fs1);
%-----------------------------------------------
figure(2);
m=1;
for i=-2:0.01:2
if(i>-0.5*pi&&i<0.5*pi)
fs1(m)=fly3_2(i,f2,inf);
m=m+1;
continue;
end
fs1(m)=0;
m=m+1;
end
title('f=0.5Hz')
hold on
plot([-2:0.01:2],fs1);
%-----------------------------------------------
figure(3);
m=1;
for
