MATLAB代码

% pi/4-DQPSK modulation
%输入一串数，输出经过差分并映射的I、Q两路数据
​
function [I,Q]=pi4_dqpskmod(data)
​
n=length(data)./2;
data1=data.*2-1;
​
Idata=zeros(1,n);
Qdata=zeros(1,n);
​
​
Idata=data1(1,1:2:2*n);     %串并变换
Qdata=data1(1,2:2:2*n);
​
I(1)=Qdata(1)*-0.5.^(0.5);              %差分编码并映射到星座图
Q(1)=Idata(1)*-0.5.^(0.5);
for i=2:n
I(i)=(I(i-1)*Qdata(i)-Q(i-1)*Idata(i))*-0.5.^(0.5);
Q(i)=(I(i-1)*Idata(i)+Q(i-1)*Qdata(i))*-0.5.^(0.5);
end

% pi/4-DQPSK demodulation
% 输入I、Q两路数，输出一路解调后的数
​
function [data]=pi4_dqpskdemod(I,Q)     %差分解调
x(1)=I(1);
y(1)=Q(1);
if (x(1)>0)Qdata(1)=0;elseQdata(1)=1;
end
​
if (y(1)>0)Idata(1)=0;elseIdata(1)=1;
end  for i=2:length(I)x(i)=I(i)*I(i-1)+Q(i)*Q(i-1);if (x(i)>0)Qdata(i)=0;elseQdata(i)=1;endy(i)=Q(i)*I(i-1)-I(i)*Q(i-1);if (y(i)>0)Idata(i)=0;elseIdata(i)=1;end
end
​
data(1,1:2:2*length(I))=Idata(1,1:length(I));  %并串变换
data(1,2:2:2*length(I))=Qdata(1,1:length(I));