qpsk_1.m

对常见的调制信号在软件无线电的通用平台下进行调制解调。所有信号均通过正交分解后

clear;
m=randn(1,10);
fc = 20;
fs = 500;
for i=1:10
    if m(i)>=1
        for j=1:500
           bit(j+(i-1)*500) = 2;
           un(j+(i-1)*500) = 0;
        end
    end
    if m(i)>=0&m(i)<1
        for j=1:500
          bit(j+(i-1)*500) = 1;
          un(j+(i-1)*500)= pi/2;
        end
    end    
    if m(i)>-1&m(i)<0 
        for j=1:500
          bit(j+(i-1)*500) = -1;
          un(j+(i-1)*500) = pi;
        end
    end    
    if m(i)<-1
        for j=1:500
          bit(j+(i-1)*500) = -2;
           un(j+(i-1)*500) = 3*pi/2;
        end
    end;
end;
t=[0:4999];
plot(t,bit);
axis([0,5000,-3,3])

I = sin(un);
Q = cos(un);

t=linspace(0,10,5000);
I=[t',I'];
Q=[t',Q'];