%   2005-3 -25
function XXXX=EN_QPSK(xxxxx)
LLLL=length(xxxxx);
aaaaaa=[0 0];
bbbbbb=[0 1];
cccccc=[1 1];
dddddd=[1 0];
for i=1:LLLL/2
    if xxxxx(1,(2*i-1):(2*i))==aaaaaa
        XXXX(i)=1;
    elseif xxxxx(1,(2*i-1):(2*i))==bbbbbb
        XXXX(i)=j;
    elseif xxxxx(1,(2*i-1):(2*i))==cccccc
        XXXX(i)=-1;
    elseif xxxxx(1,(2*i-1):(2*i))==dddddd
        XXXX(i)=-j;
    end
end