Mercurial > octave-antonio
view scripts/signal/stft.m @ 20165:f1d0f506ee78 stable
doc: Update more docstrings to have one sentence summary as first line.
Reviewed optimization, polynomial, signal script directories.
* scripts/optimization/fminbnd.m, scripts/optimization/fminsearch.m,
scripts/optimization/fminunc.m, scripts/optimization/fsolve.m,
scripts/optimization/fzero.m, scripts/optimization/glpk.m,
scripts/optimization/lsqnonneg.m, scripts/optimization/pqpnonneg.m,
scripts/optimization/qp.m, scripts/optimization/sqp.m,
scripts/polynomial/compan.m, scripts/polynomial/mkpp.m,
scripts/polynomial/mpoles.m, scripts/polynomial/pchip.m,
scripts/polynomial/poly.m, scripts/polynomial/polyaffine.m,
scripts/polynomial/polyder.m, scripts/polynomial/polyeig.m,
scripts/polynomial/polyfit.m, scripts/polynomial/polygcd.m,
scripts/polynomial/polyint.m, scripts/polynomial/polyout.m,
scripts/polynomial/polyval.m, scripts/polynomial/ppder.m,
scripts/polynomial/ppint.m, scripts/polynomial/ppjumps.m,
scripts/polynomial/ppval.m, scripts/polynomial/residue.m,
scripts/polynomial/roots.m, scripts/polynomial/spline.m,
scripts/polynomial/splinefit.m, scripts/polynomial/unmkpp.m,
scripts/signal/arch_fit.m, scripts/signal/arch_rnd.m,
scripts/signal/arma_rnd.m, scripts/signal/autoreg_matrix.m,
scripts/signal/bartlett.m, scripts/signal/blackman.m, scripts/signal/detrend.m,
scripts/signal/diffpara.m, scripts/signal/durbinlevinson.m,
scripts/signal/fftconv.m, scripts/signal/fftfilt.m, scripts/signal/fftshift.m,
scripts/signal/filter2.m, scripts/signal/freqz.m, scripts/signal/hamming.m,
scripts/signal/hanning.m, scripts/signal/hurst.m, scripts/signal/ifftshift.m,
scripts/signal/periodogram.m, scripts/signal/sinc.m, scripts/signal/sinetone.m,
scripts/signal/sinewave.m, scripts/signal/spectral_adf.m,
scripts/signal/spectral_xdf.m, scripts/signal/spencer.m, scripts/signal/stft.m,
scripts/signal/synthesis.m, scripts/signal/unwrap.m,
scripts/signal/yulewalker.m:
Update more docstrings to have one sentence summary as first line.
author | Rik <rik@octave.org> |
---|---|
date | Mon, 04 May 2015 21:50:57 -0700 |
parents | 4197fc428c7d |
children |
line wrap: on
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## Copyright (C) 1995-2015 Andreas Weingessel ## ## This file is part of Octave. ## ## Octave 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. ## ## Octave 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 Octave; see the file COPYING. If not, see ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {Function File} {@var{y} =} stft (@var{x}) ## @deftypefnx {Function File} {@var{y} =} stft (@var{x}, @var{win_size}) ## @deftypefnx {Function File} {@var{y} =} stft (@var{x}, @var{win_size}, @var{inc}) ## @deftypefnx {Function File} {@var{y} =} stft (@var{x}, @var{win_size}, @var{inc}, @var{num_coef}) ## @deftypefnx {Function File} {@var{y} =} stft (@var{x}, @var{win_size}, @var{inc}, @var{num_coef}, @var{win_type}) ## @deftypefnx {Function File} {[@var{y}, @var{c}] =} stft (@dots{}) ## Compute the short-time Fourier transform of the vector @var{x} with ## @var{num_coef} coefficients by applying a window of @var{win_size} data ## points and an increment of @var{inc} points. ## ## Before computing the Fourier transform, one of the following windows ## is applied: ## ## @table @asis ## @item @qcode{"hanning"} ## win_type = 1 ## ## @item @qcode{"hamming"} ## win_type = 2 ## ## @item @qcode{"rectangle"} ## win_type = 3 ## @end table ## ## The window names can be passed as strings or by the @var{win_type} number. ## ## The following defaults are used for unspecified arguments: ## @var{win_size} = 80, @var{inc} = 24, @var{num_coef} = 64, and ## @var{win_type} = 1. ## ## @code{@var{y} = stft (@var{x}, @dots{})} returns the absolute values of the ## Fourier coefficients according to the @var{num_coef} positive frequencies. ## ## @code{[@var{y}, @var{c}] = stft (@code{x}, @dots{})} returns the entire ## STFT-matrix @var{y} and a 3-element vector @var{c} containing the window ## size, increment, and window type, which is needed by the @code{synthesis} ## function. ## @seealso{synthesis} ## @end deftypefn ## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at> ## Description: Short-Time Fourier Transform function [y, c] = stft (x, win_size = 80, inc = 24, num_coef = 64, win_type = 1) if (nargin < 1 || nargin > 5) print_usage (); endif if (ischar (win_type)) switch (tolower (win_type)) case "hanning" win_type = 1; case "hamming" win_type = 2; case "rectangle" win_type = 3; otherwise error ("stft: unknown window type '%s'", win_type); endswitch endif ## Check whether X is a vector. if (! isvector (x)) error ("stft: X must be a vector"); endif x = x(:); ncoef = 2 * num_coef; if (win_size > ncoef) win_size = ncoef; printf ("stft: window size adjusted to %f\n", win_size); endif num_win = fix ((rows (x) - win_size) / inc); ## compute the window coefficients switch (win_type) case 1 win_coef = hanning (win_size); case 2 win_coef = hamming (win_size); case 3 win_coef = ones (win_size, 1); endswitch ## Create a matrix Z whose columns contain the windowed time-slices. z = zeros (ncoef, num_win + 1); start = 1; for i = 0:num_win z(1:win_size, i+1) = x(start:start+win_size-1) .* win_coef; start = start + inc; endfor y = fft (z); if (nargout == 1) y = abs (y(1:num_coef, :)); else c = [win_size, inc, win_type]; endif endfunction