【通信】基于matlab跳频通信系统【含Matlab源码 967期】

一、简介

1 扩频通信基础







2 跳频通信原理

二、源代码

clc;clear;
g=40;fs=100000; 
r=-10;delay=0;  
sig1=round(rand(1,g));     %产生随机信号源 
signal1=[];   
for k=1:g                  %离散点化     
if sig1(1,k)==0          
sig=-ones(1,1000);         % bit 0设置1000个样点     
else          
sig=ones(1,1000);          % bit 1设置1000个样点     
end      
signal1=[signal1 sig];
end  
figure(1)  
plot(signal1,'b','linewidth',1);           %信源波形
grid on;
axis([-100 1000*g -1.5 1.5]); 
title('信号源')

T0=200; f0=1/T0; 
T1=400; f1=1/T1;  
u0=gensig('sin',T0,1000*g-1,1);
u0=rot90(u0); u1=gensig('sin',T1,1000*g-1,1);
u1=rot90(u1); y0=u0.*sign(-signal1+1); 
y1=u1.*sign(signal1+1);  
SignalFSK=y0+y1;          % 生成的FSK信号 
figure(2);
% subplot(2,1,1);  
plot(SignalFSK)           % FSK信号的时域波形 
axis([-100 1000*g -3 3]); 
title('SignalFSK') 

% % FSK信号频谱 
% subplot(2,1,2)  
% Plot_f(SignalFSK ,fs); 
% title('FSK调制后的频谱'); 

t1=(0:100*pi/999:100*pi);            
t2=(0:110*pi/999:110*pi);                 
t3=(0:120*pi/999:120*pi);                            
t4=(0:130*pi/999:130*pi);                   
t5=(0:140*pi/999:140*pi);                
t6=(0:150*pi/999:150*pi);        
t7=(0:160*pi/999:160*pi);   
t8=(0:170*pi/999:170*pi);   
c1=cos(t1);                      
c2=cos(t2);  
c3=cos(t3);                      
c4=cos(t4);
c5=cos(t5);
c6=cos(t6); 
c7=cos(t7); 
c8=cos(t8); 
adr1=Mcreate(1001203);  
adr1=[adr1,adr1(1),adr1(2)];      %用户地址为初始m序列
fh_seq1= []; 
for k=1:g   
seq_1=adr1(3*k-2)*2^2+adr1(3*k-1)*2+adr1(3*k);   
fh_seq1=[fh_seq1 seq_1];              %生成用户载波序列 
end

spread_signal1=[];           %用户一载波
fhp=[]; 
for k=1:g      
c=fh_seq1(k);     
switch(c)         
case(0)              
spread_signal1=[spread_signal1 c8];         
case(1)              
spread_signal1=[spread_signal1 c1];                %形成随机载频序列         
case(2)              
spread_signal1=[spread_signal1 c2];         
case(3)              
spread_signal1=[spread_signal1 c3];         
case(4)              
spread_signal1=[spread_signal1 c4];         
case(5)                      
spread_signal1=[spread_signal1 c5]; 
case(6)              
spread_signal1=[spread_signal1 c6];         
case(7)              
spread_signal1=[spread_signal1 c7];                
end      
fhp=[fhp (500*c+5000)]; 
end
function seq = Mcreate( prim_poly )
connections=de2bi(prim_poly);
N=length(connections); 
tmp1=fliplr(connections); 
con=tmp1(2:N);  
m=length(connections)-1;         
L=2^m-1;                        
registers=[zeros(1,m-1) 1];      
seq(1)=registers(m);            
for ii=1:L      
seq(ii)=registers(m);     
tmp2=registers*con';     
tmp2=mod(tmp2,2);      
registers(2:m)=registers(1:m-1);     
registers(1)=tmp2; 
end; 
end
function Plot_f( SignalFSK ,fs)    
nfft=fs+1;   
Y = fft(SignalFSK,nfft); 
PSignalFSK = Y.* conj(Y)/nfft; 
f = fs*(0:nfft/2)/nfft;     

axis([0 10000 -inf inf]); 
end

三、运行结果

四、备注

版本：2014a