北邮DSP matlab实验.docx

1、北邮DSP matlab实验1.单位抽样序列n=-10:10; y=zeros(1,10),1,zeros(1,10);stem(n,y) axis(-10,10,0,2);2.单位阶跃序列n=-10:10; y=zeros(1,10),ones(1,11);stem(n,y) axis(-10,10,0,2);3.正弦序列n=0:60; A = 5; f = 200; Fs = 5000; fai = pi/3;y=A*sin(2*pi*f*n/Fs + fai);stem(n,y) axis(0,60,-5,5);4.复正弦序列n = 0:20;w = pi/10;x = exp(j*n*

2、w);subplot(3,2,1); stem (n,x);title(x);xlabel(n);subplot(3,2,2); stem (n,real(x);title(实部);xlabel(n);subplot(3,2,3); stem (n,imag(x);title(虚部);xlabel(n);subplot(3,2,4); stem (n,abs(x);title(振幅);xlabel(n);subplot(3,2,5); stem (n,(180/pi)*angle(x);title(相位);xlabel(n);5.指数序列n = 0:10;y = 1.5.n;stem(n,y)

3、6.复指数序列n = -10:1:10;alpha = -0.1+0.3j;x = exp(alpha*n);subplot(2,2,1); stem (n,real(x);title(实部);xlabel(n);subplot(2,2,2); stem (n,imag(x);title(虚部);xlabel(n);subplot(2,2,3); stem (n,abs(x);title(振幅);xlabel(n);subplot(2,2,4); stem (n,(180/pi)*angle(x);title(相位);xlabel(n);二、1. h(n)n = -20:20; stem(n,

4、y); a=1,0.75,0.125; b=1,-1; x=zeros(1,20),1,zeros(1,20); n = -20:20;y = filter(b,a,x);stem(n,y);理论计算：h(n) = 6*(-0.5).n - 5*(-0.25).n ;当n取0,1,2，.，10时，h(n）计算结果如下： 1.0000 -1.7500 1.1875 -0.6719 0.3555 -0.1826 0.0925 -0.0466 0.0234 -0.0117 0.0059与matlab程序画的单位冲击响应的图形一致。g(n)x2=zeros(1,20),ones(1,21);y2 =

5、filter(b,a,x2);stem(n,y2);理论计算：g(n) = 4*(1-(-0.5).(n+1) - 4*(1-(-0.25).(n+1);当n取0,1,2，.，10时，h(n）计算结果如下： 1.0000 -0.7500 0.4375 -0.2344 0.1211 -0.0615 0.0310 -0.0156 0.0078 -0.00390.0020与matlab程序画的单位阶跃响应的图形一致。2.h(n) b= 0,1,1,1,1; a=4; x=zeros(1,20),1,zeros(1,20); n = -20:20; y = filter(b,a,x); stem(n,

6、y)理论计算：h(n) = 0.25(delta(n-1)+delta(n-2)+delta(n-3)+delta(n-4)与程序计算结果相符g(n)x2=zeros(1,20),ones(1,21);y2 = filter(b,a,x2);stem(n,y2);理论计算：g(n) = 0.25(u(n-1)+u(n-2)+u(n-3)+u(n-4)与程序计算结果一致。三、 b=0.0528,0.0797,0.1295,0.797,0.0528; a=1,-1.8107,2.4947,-1.8801,0.9537,-0.2336; zplane(b,a)零极点图H,w = freqz(b,a,100,whole);plot(w,abs(H)axis(0,2*pi,0,14);xlabel(w); ylabel(|H|);幅度频率响应特线