qam_modulation.m

详细的介绍MATLAB 7 的功能

function [y1,y2]=Qam_modulation(x)
%QAM_modulation
%对产生的二进制序列进行QAM调制
    %=====首先进行串并转换，将原二进制序列转换成两路信号
N=length(x);
a=1:2:N;
y1=x(a);
y2=x(a+1);
    %=====分别对两路信号进行QPSK调制
          %======对两路信号分别进行2－4电平变换
a=1:2:N/2;
temp1=y1(a);
temp2=y1(a+1);
y11=temp1*2+temp2;
temp1=y2(a);
temp2=y2(a+1);
y22=temp1*2+temp2;
          %=======对两路信号分别进行相位调制
a=1:N/4;
y1=(y11*2-1-4)*1.*cos(2*pi*a);
y2=(y22*2-1-4)*1.*cos(2*pi*a);
y1(find(y11==0))=-3;
y1(find(y11==1))=-1;
y1(find(y11==3))=1;
y1(find(y11==2))=3;
y2(find(y22==0))=-3;
y2(find(y22==1))=-1;
y2(find(y22==3))=1;
y2(find(y22==2))=3;