function y = mod_qam_020612b (x,n,M)

global k Fc Fd Fs n Fs_n;

%modulate x with wc.
Wc_I = cos(2*pi*n*Fc);      %generate the Carrier Waveform
Wc_Q = sin(2*pi*n*Fc); 

    I = fix ( x/4 );
    Q = mod ( x,4 );
    
    d = sqrt(2) / (4-1);
    
    y_I = (-d/2*3 + d * I).*Wc_I;
    y_Q = (-d/2*3 + d * Q).*Wc_Q;
    
    y = y_I + y_Q;