matlab与通信系统仿真程序及图
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实验一
2:for i=1:50,j=1:50;
A(i,j)=i+j-1;
end
C=flipud(A),B=fliplr(A),A(1:10,1:10)=zeros;D=A
3:clear;
a=255*rand(50);disp(a),
a(find(a<128))=0;
a(find(a>128))=255;
w=a;
disp(w)
实验二:
1:(1)
clear;n=0:23;
N=12;
y1=sin(2*4*pi*n/N);y2=sin(2*5*pi*n/N);y3=sin(2*7*pi*n/N);y4=sin(2*10*pi*n/N);
plot(n,y1,'+r-',n,y2,'-.',n,y3,'k-',n,y4,'*g-');axis([0 25 -1 2 ]);xlabel('横轴n');ylabel('纵轴y');
text(0.8,0.9,'y1');text(19.6,0.9,'y2');text(14,0.9,'y3');text(5,0.9,'y4');
title('plot tu xing');legend('y1=sin(2*4*pi*n/N)','y2=sin(2*5*pi*n/N)','y3=sin(2*7*pi*n/N)','y4=sin(2*10*pi*n/N)')(2)
clear;
n=0:23;
N=12;
y1=sin(2*4*pi*n/N);y2=sin(2*5*pi*n/N);y3=sin(2*7*pi*n/N);y4=sin(2*10*pi*n/N);
stem(n,y1,'+r-');hold on;
stem(n,y2,'b-');hold on;
stem(n,y3,'k-');hold on;
stem(n,y4,'*g-');axis([0,25,-2,4]);
xlabel('横轴n');ylabel('纵轴y');
text(0.8,1.2,'y1');text(3,1.4,'y2');text(14,1.2,'y3');text(10.9,1.3,'y4');
title('n from 0 to 23');legend('y1=sin(2*4*pi*n/N)','y2=sin(2*5*pi*n/N)','y3=sin(2*7*pi*n/N)','y4=sin(2*10*pi*n/N)') 2:
clear all;
N=input('input N=');
T=1;
fs=1/T;
N_sample=128;
dt=1/N_sample;
t=0:dt:10*T-dt;
n=-N:N;
Fn=(-1/2)*sinc(n/2).*exp(-j*n*pi/2);
Fn(N+1)=0;
ft=zeros(1,length(t));
for m=-N:N;
ft=ft+ Fn(m+N+1)*exp(j*m*pi*2*fs*t);
end
plot(t,ft);
legend('时域曲线ft=ft+ Fn(m+N+1)*exp(j*m*pi*2*fs*t)',4)
3:
N_sample=128;
dt=1/N_sample;
t=0:dt:1-dt;
st=[ones(1,N_sample/2),-ones(1,N_sample/2)];
subplot(311);plot(t,st);axis([0 1 -2 2]);xlabel('t');ylabel('s(t)'); subplot(312);
[f,sf]=T2F(t,st);
plot(f,abs(sf));
hold on;
axis([-10 10 0 1]);
xlabel('f');ylabel('|S(f)|');
sff=(-1/2)*exp(-j*f*pi/2).*sinc(f/2);
plot(f,abs(sff));
[t,st]=F2T(f,sf);
subplot(313);
axis([0 1 -2 2]);
xlabel('t');ylabel('恢复的s(t)');
plot(t,st)
子函数:
(1):
function[t,st]=F2T(f,sf)
df=f(2)-f(1);
Fmx=f(end)-f(1)+df;
dt=1/Fmx;
N=length(sf);
T=dt*N;
t=0:dt:T-dt;
sff=fftshift(sf);
st=Fmx*ifft(sff);
(2):
function[f,sf]=T2F(t,st)
dt=t(2)-t(1);
T=t(end);
df=1/T;
N=length(st);
f=-N/2*df:df:N/2*df-df;
sf=fft(st);
sf=T/N*fftshift(sf);
2图:
M=4 M=5
M=7 M=10
M=4 M=5
M=7 M=10
N=10 N=100
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