qpsk_mod.asv

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function [d_symb]=qpsk_mod(i,d)  % qpsk modulation
% 
% pairs of bits,b(i),b(i+1)are mapped to complex-valued modulation symbols d_symb=Re+j*Im 
% modulation scheme:
%
%
%
numbits=168;
for n=1:2:numbits     
switch d(n)
    case 0
    Re(n)=1/sqrt(2); 
    case 1
    Re(n)=-1/sqrt(2);
end
switch d(n+1)
    case 0
    Im(n)=1/sqrt(2);
    case 1
    Im(n)=-1/sqrt(2);
end
d_symb(floor(n/2)+1)=Re(n)+j*Im(n);
end