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: