idft.m

来自「Matlab时频分析工具箱,希望能对大家有所帮助啊」· M 代码 · 共 43 行

function f=idft(f,N,dim)
%IDFT  Inverse DFT
%   Usage: f=idft(f);
%          f=idft(f,N,dim);
%
%   This function computes a normalized inverse discrete Fourier transform.
%   This is nothing but a scaled version of the output from IFFT. The
%   function takes exactly the same arguments as IFFT. See the help on IFFT
%   for a throurough description.
%
%   SEE ALSO:  DFT

% This program is free software: you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation, either version 3 of the License, or
% (at your option) any later version.
% 
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
% 
% You should have received a copy of the GNU General Public License
% along with this program.  If not, see <http://www.gnu.org/licenses/>.

error(nargchk(1,3,nargin));

if nargin<3
  dim=[];  
end;

if nargin<2
  N=[];
end;

[f,N,Ls,W,dim,permutedsize,order]=assert_sigreshape_pre(f,N,dim,'IDFT');

% Force IFFT along dimension 1, since we have permuted the dimensions
% manually
f=ifft(f,N,1)*sqrt(N);

f=assert_sigreshape_post(f,dim,permutedsize,order);