信号分析与处理作业——北京科技大学
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信号处理作业1
矩形脉冲周期信号频谱分析的MATLAB实现
程序:
t=-15:0.001:15;
x=0.5*(square(t,20)+1);
figure(1),plot(t-pi/5,x),grid;
title('矩形脉冲周期信号的时域波形');
axis([-15 15 -0.1 1.1]);
for i=1:61
k(i)=i-31;
if k(i)~=0
a(i)=2/(pi*k(i))*sin(pi*k(i)/5);
realc(i)=a(i)/2;
b(i)=0*k(i);
c(i)=sqrt(realc(i)*realc(i)+b(i)*b(i));
if a(i)>=0
phase(i)=0;
else
phase(i)=180;
end
elseif k(i)==0
a(i)= 2*0.4*pi/(2*pi);
realc(i)=a(i)/2;
b(i)=0*k(i);
c(i)=sqrt(realc(i)*realc(i)+b(i)*b(i));
phase(i)=0;
end
end
figure(2);
subplot(2,1,1);
stem(k,realc,'.');grid;
title('实频谱'); axis([-30 30 -0.05 0.21]);
subplot(2,1,2)
stem(k,b,'.');grid;
title('虚频谱');
axis([-30 30 -0.05 0.21]);
figure(3)
subplot(2,1,1);
stem(k,c,'.');grid;
title('频谱幅值');
axis([-30 30 -0.02 0.2]);
subplot(2,1,2);
stem(k,phase,'.');grid;
title('频谱相位');
axis([-30 30 -20 200]);
结果截图:
以下截图按顺序表示: