fun_ddp.m

包含软件无线电中软件接收机的信号识别功能

function ddp=fun_ddp(I,Q)
N=length(I);
p=zeros(1,N);
temp=0.001;%门限
for i=1:N
    if abs(I(i))<=temp
        if Q(i)>=temp
            p(i)=pi/2;
        else
            p(i)=-pi/2;
        end
    end
    if I(i)<-temp
        if Q(i)>temp
            p(i)=atan(Q(i)/I(i))+pi;
        end
        if Q(i)<-temp
            p(i)=atan(Q(i)/I(i))-pi;
        end
        if(abs(Q(i))<temp)
            p(i)=pi;
        end
    end
    if I>temp
        p(i)=atan(Q(i)/I(i));
    end
end
mp=sum(p)/N;
p=p-mp;
ddp=sqrt(sum(p.*p)/N-(sum(p)/N).*(sum(p)/N));