通信系统仿真实验二.docx
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通信系统仿真实验二
function[u11,uc1,uam1]=dangeshurudeAMbo(a1,a2,f1,f2,ma)
%a1调制信号的幅度;
%f1调制信号的频率;
%a2载波信号的幅度;
%f2载波信号的频率;
%ma调制度
fs=20*max(f1,f2);
t=0:
1/fs:
2/min(f1,f2);
u11=a1*cos(2*pi*f1*t);%设调制信号频率
uc1=a2*cos(2*pi*f2*t);%设载波频率
uam1=(1+ma*u11).*uc1;%AM振幅调制
X=fftshift(fft(u11));
Y=fftshift(fft(uc1));
Z=fftshift(fft(uam1));
F=linspace(-fs/2,fs/2,length(t));
subplot(3,1,1);plot(t,u11);gridon
subplot(3,1,2);plot(t,uc1);gridon
subplot(3,1,3);plot(t,uam1);gridon
figure;
subplot(3,1,1);plot(F,abs(X));gridon
subplot(3,1,2);plot(F,abs(Y));gridon
subplot(3,1,3);plot(F,abs(Z));gridon
s=uam1.*uc1;
Rp=3;%信号衰减幅度
Rs=60;%信号衰减幅度
Wp=40/500;%通带截止频率
Ws=150/500;%阻带截止频率
[n,Wn]=ellipord(Wp,Ws,Rp,Rs);%阶数n
[b,a]=ellip(n,Rp,Rs,Wn);%传递函数分子分母b,a
y11=5*filter(b,a,s);
A=fftshift(fft(u11));
B=fftshift(fft(y11));
F=linspace(-fs/2,fs/2,length(t));
figure;
subplot(4,1,1);plot(t,u11);gridon
subplot(4,1,2);plot(t,y11);gridon
subplot(4,1,3);plot(F,abs(A));gridon
subplot(4,1,4);plot(F,abs(B));gridon
输入命令[u11,uc1,uam1]=dangeshurudeAMbo(1,1,200,3200,0.3)
function[u11,uc1,uam1]=duogeshurudeAMbo(a11,a12,a13,a2,f11,f12,f13,f2,ma)
%a11调制信号1的幅度;
%a12调制信号2的幅度;
%a13调制信号3的幅度;
%f11调制信号1的频率;
%f12调制信号2的频率;
%f13调制信号3的频率;
%a2载波信号的幅度;
%f2载波信号的频率;
%ma调制度
fs=20*f2;
t=0:
1/fs:
2/f11;
u11=a11*cos(2*pi*f11*t)+a12*cos(2*pi*f12*t)+a13*cos(2*pi*f13*t);%设调制信号频率
uc1=a2*cos(2*pi*f2*t);%设载波频率
uam1=(1+ma*u11).*uc1;%AM振幅调制
X=fftshift(fft(u11));
Y=fftshift(fft(uc1));
Z=fftshift(fft(uam1));
F=linspace(-fs/2,fs/2,length(t));
subplot(3,1,1);plot(t,u11);gridon
subplot(3,1,2);plot(t,uc1);gridon
subplot(3,1,3);plot(t,uam1);gridon
figure;
subplot(3,1,1);plot(F,abs(X));gridon
subplot(3,1,2);plot(F,abs(Y));gridon
subplot(3,1,3);plot(F,abs(Z));gridon
s=uam1.*uc1;
Rp=3;%信号衰减幅度
Rs=60;%信号衰减幅度
Wp=40/500;%通带截止频率
Ws=150/500;%阻带截止频率
[n,Wn]=ellipord(Wp,Ws,Rp,Rs);%阶数n
[b,a]=ellip(n,Rp,Rs,Wn);%传递函数分子分母b,a
y11=5*filter(b,a,s);
A=fftshift(fft(u11));
B=fftshift(fft(y11));
F=linspace(-fs/2,fs/2,length(t));
figure;
subplot(4,1,1);plot(t,u11);gridon
subplot(4,1,2);plot(t,y11);gridon
subplot(4,1,3);plot(F,abs(A));gridon
subplot(4,1,4);plot(F,abs(B));gridon
输入命令[u11,uc1,uam1]=duogeshurudeAMbo(1,2,5,1,200,250,300,3200,0.3)
DSB振幅调制与解调制的MATLAB仿真
function[u21,uc2,udsb1]=dangexinhaodsbbo(a1,a2,f1,f2)
%a1调制信号的幅度;
%f1调制信号的频率;
%a2载波信号的幅度;
%f2载波信号的频率;
fs=20*max(f1,f2);
t=0:
1/fs:
2/min(f1,f2);
k=1;
u21=a1*cos(2*pi*f1*t);%设调制信号频率
uc2=a2*cos(2*pi*f2*t);%设载波频率
udsb1=k*u21.*uc2;%调制信号与载波相乘
subplot(3,1,1);plot(t,u21);gridon
subplot(3,1,2);plot(t,uc2);gridon
subplot(3,1,3);plot(t,udsb1);gridon
X=fftshift(fft(u21));
Y=fftshift(fft(uc2));
Z=fftshift(fft(udsb1));
figure;
F=linspace(-fs/2,fs/2,length(t));
subplot(3,1,1);plot(F,abs(X));gridon
subplot(3,1,2);plot(F,abs(Y));gridon
subplot(3,1,3);plot(F,abs(Z));gridon
s1=udsb1.*uc2;
Rp=3;
Rs=60;%信号衰减幅度
Wp=40/500;%通带截止频率
Ws=200/500;%阻带截止频率
[n,Wn]=ellipord(Wp,Ws,Rp,Rs);%阶数n
[b,a]=ellip(n,Rp,Rs,Wn);%传递函数分子分母b,a
y21=5*filter(b,a,s1);
A=fftshift(fft(u21));
B=fftshift(fft(y21));
F=linspace(-fs/2,fs/2,length(t));
figure;
subplot(4,1,1);plot(t,u21);gridon
subplot(4,1,2);plot(t,y21);gridon
subplot(4,1,3);plot(F,abs(A));gridon
subplot(4,1,4);plot(F,abs(B));gridon
输入命令[u21,uc2,udsb1]=dangexinhaodsbbo(1,2,200,3500)
DSB振幅调制与解调制的MATLAB仿真
function[u21,uc2,udsb1]=duogexinhaodsbbo(a11,a12,a13,a2,f11,f12,f13,f2)
%a11调制信号1的幅度;
%a12调制信号2的幅度;
%a13调制信号3的幅度;
%f11调制信号1的频率;
%f12调制信号2的频率;
%f13调制信号3的频率;
%a2载波信号的幅度;
%f2载波信号的频率;
fs=20*f2;
k=1;
t=0:
1/fs:
2/f11;
u21=a11*cos(2*pi*f11*t)+a12*cos(2*pi*f12*t)+a13*cos(2*pi*f13*t);%设调制信号频率
uc2=a2*cos(2*pi*f2*t);%设载波频率
udsb1=k*u21.*uc2;%调制信号与载波相乘
subplot(3,1,1);plot(t,u21);gridon
subplot(3,1,2);plot(t,uc2);gridon
subplot(3,1,3);plot(t,udsb1);gridon
X=fftshift(fft(u21));
Y=fftshift(fft(uc2));
Z=fftshift(fft(udsb1));
figure;
F=linspace(-fs/2,fs/2,length(t));
subplot(3,1,1);plot(F,abs(X));gridon
subplot(3,1,2);plot(F,abs(Y));gridon
subplot(3,1,3);plot(F,abs(Z));gridon
s1=udsb1.*uc2;
Rp=3;
Rs=60;%信号衰减幅度
Wp=40/500;%通带截止频率
Ws=200/500;%阻带截止频率
[n,Wn]=ellipord(Wp,Ws,Rp,Rs);%阶数n
[b,a]=ellip(n,Rp,Rs,Wn);%传递函数分子分母b,a
y21=5*filter(b,a,s1);
A=fftshift(fft(u21));
B=fftshift(fft(y21));
F=linspace(-fs/2,fs/2,length(t));
figure;
subplot(4,1,1);plot(t,u21);gridon
subplot(4,1,2);plot(t,y21);gridon
subplot(4,1,3);plot(F,abs(A));gridon
subplot(4,1,4);plot(F,abs(B));gridon
输入命令[u21,uc2,udsb1]=duogexinhaodsbbo(8,2,5,1,200,500,800,4000)