www.pudn.com > QPSK.rar > QPSK.m

%信号分选 
clear all; 
 
fc=14400000;   %载波频率 
fd=100000;       %信号带宽 
f0=20400000; 
modulation=0; 
 
Ns=6400; 
t=0:1/fs:(Ns-1)/fs; 
k=1:Ns; 
 
SKN=0; 
 
q=(randint(500,1,2)); 
 
len = length(modulation); 
 
for N=1:1:len 
    %数字信号生成,对应采样点生成  
    bandwidth=fd(N); 
    NS=round(fs/bandwidth); 
    q1=q(:,ones(1,NS))'; 
    qq=q1(:)';   
     
    if modulation(N)==2 
    %qpsk信号生成   
    %需要信号重新生成   
    q2=randint(500,1,4);   
     
    NS2=round(fs/fd(N)); 
    q21=q2(:,ones(1,NS2))'; 
    qq2=q21(:)';   
 
    CC=cos(2*pi*fc(N)*t);SS=sin(2*pi*fc(N)*t); 
    SK=CC.*cos(qq2(1:Ns)*pi/2)-SS.*sin(qq2(1:Ns)*pi/2); 
    end 
      
    SKN=K; 
          
    clear CC; 
    clear SK; 
    clear SS;  
    clear qq; 
    clear q1; 
end 
%信号的频谱图 
SkF=fft(SKN); 
figure(1); 
subplot(2,1,1);plot(k,SKN);grid;title('多路信号时域图'); 
subplot(2,1,2);plot(k*fs/Ns,abs(SkF));grid;title('多路信号频域图');