izak.m

来自「linear time－frequency toolbox」· M 代码 · 共 34 行

function f=izak(c);
%IZAK  Inverse Zak transform
%   Usage:  f=izak(c);
%
%   IZAK(c) computes the inverse Zak transform of c. The parameter of
%   the Zak transform is deduced from the size of c.
%
%   SEE ALSO:  ZAK
%
%   REFERENCES:
%     H. Bölcskei and F. Hlawatsch. Discrete Zak transforms, polyphase transforms,
%     and applications. IEEE Trans. Signal Process., 45(4):851-866, april 1997.
%     
%     A. J. E. M. Janssen. Duality and biorthogonality for discrete-time
%     Weyl-Heisenberg frames. Unclassified report, Philips Electronics, 002/94.

error(nargchk(1,1,nargin));

a=size(c,1);
N=size(c,2);
W=size(c,3);

L=a*N;

% Create output matrix.
f=zeros(L,W);

for ii=1:W
  % Iterate through third dimension of c.
  % We use a normalized DFT, as this gives the correct normalization
  % of the Zak transform.
  f(:,ii)=reshape(idft(c(:,:,ii),[],2),L,1);
end;