function rmax = demod_Rmax (Acn)
%Compute the MAX value of R.
%   Rmax=max |DFT(Acn(i))|^2 /N
%

%[yi,yq] = demod_iq (y);
%N = length(yi);

%Ai = sqrt( yi.*yi + yq.*yq );
%mean_Ai = ( sum(Ai) ) / N;
%An =  Ai / mean_Ai;
%Acn = An -1;

N = length(Acn);
% Compute |DFT(Acn(i))|^2
%Y = fft(Acn,512);
Y = fft(Acn);
YY = Y.* conj(Y);

rmax = max(YY) / N;