comp_idgt.m

linear time－frequency toolbox

function f=comp_idgt(coef,g,a,M,L)
%COMP_IDGT  Compute IDGT
%   Usage:  f=comp_idgt(c,g,a,M,L);
%
%   Input parameters:
%         c     : Array of coefficients.
%         g     : Window function.
%         a     : Length of time shift.
%         M     : Number of modulations.
%         L     : length of transform.
%   Output parameters:
%         f     : Signal.
%

% AUTHOR : Peter Soendergaard.

b=L/M;
N=L/a;

Lwindow=size(g,1);
W=size(coef,3);

if L==Lwindow
  % Do full-window algorithm.
  % Apply ifft to the coefficients.
  coef=ifft(reshape(coef,M,N*W))*sqrt(M);

  % Get the factorization of the window.
  % Call the computational subroutine.
  % Recover from the factorization
  
  gf = comp_wfac(g,a,M);      
  f  = comp_idgt_fw(coef,gf,L,a,M);
  
else
  % Do filter bank algorithm.
  % Call the computational subroutine.
  f=comp_idgt_fb(coef,g,a,M);

end;