comp_rdgt.m

linear time－frequency toolbox

function [cout]=comp_rdgt(cin,a)
%COMP_RDGT Compute real DGT
%

M=size(cin,1);
N=size(cin,2);
W=size(cin,3);
L=N*a;

Mhalf=ceil(M/2);
Mend=Mhalf*2-1;

cout=zeros(M,N,W);

% Copy the first coefficient, it is real
cout(1,:,:)=real(cin(1,:,:));

% Copy the cosine-part of the coefficients.
cout(2:2:Mend,:,:)=real(cin(2:Mhalf,:,:))*sqrt(2);

% Copy the sine-part of the coefficients.
cout(3:2:Mend,:,:)=-imag(cin(2:Mhalf,:,:))*sqrt(2);

% If M is even, we must also copy the Niquest-wave
% (it is real)
if mod(M,2)==0
  cout(M,:,:)=real(cin(M/2+1,:,:));
end;

cout=reshape(cout,M*N,W);