soft_decision.m

RS编解码的Matlab源代码

function out= soft_decision(in)
%用于对8PSK解调的软判决,8*10电平,量化值介于0到7
n=length(in);
x=real(in);
y=imag(in);
out=zeros(1,n);
sita=zeros(1,n);
tangent=y./x;
arctangent=atan(tangent);
for i=1:n
    if (x(i)>=0)&(y(i)>=0)
        sita(i)=arctangent(i)*180/pi;
    elseif (x(i)>0)&(y(i)<0)
        sita(i)=arctangent(i)*180/pi+360;
    elseif (x(i)<0)&(y(i)>=0)
        sita(i)=arctangent(i)*180/pi+180;
    elseif (x(i)<=0)&(y(i)<0)
        sita(i)=arctangent(i)*180/pi+180;
    end
end
out=(floor(sita./4.5+0.5))./10;