dft.m

来自「很多matlab的源代码」· M 代码 · 共 17 行

function [Xk] = dft(xn,N)
%N=4;
%xn = [0 ,1 ,2, 3];

% Computes Discrete Fourier Transform
% -------------------------------------------------
% [Xk] = dft(xn,N)
% Xk = DFT coeff . array over 0 <= k <= N-1
% xn = N-point finite-duration sequence
% N = Length of DFT
%
n = [0:1:N-1];              % row vector for n
k = [0:1:N-1];              % row vector for k
WN = exp(-j*2*pi/N);        % Wn factor
nk = n'*k;                  % creates a N by matrix of nk values
WNnk = WN.^nk;              % DFT matrix
Xk = xn*WNnk;             % row vector for DFT coefficients