Mercurial > octave

annotate scripts/signal/stft.m @ 30564:796f54d4ddbf stable

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
update Octave Project Developers copyright for the new year In files that have the "Octave Project Developers" copyright notice, update for 2021. In all .txi and .texi files except gpl.txi and gpl.texi in the doc/liboctave and doc/interpreter directories, change the copyright to "Octave Project Developers", the same as used for other source files. Update copyright notices for 2022 (not done since 2019). For gpl.txi and gpl.texi, change the copyright notice to be "Free Software Foundation, Inc." and leave the date at 2007 only because this file only contains the text of the GPL, not anything created by the Octave Project Developers. Add Paul Thomas to contributors.in.
author John W. Eaton <jwe@octave.org>
date Tue, 28 Dec 2021 18:22:40 -0500
parents 7854d5752dd2
children fd29c7a50a78
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
27923
bd51beb6205e update formatting of copyright notices
John W. Eaton <jwe@octave.org>
parents: 27919
diff changeset
1 ########################################################################
bd51beb6205e update formatting of copyright notices
John W. Eaton <jwe@octave.org>
parents: 27919
diff changeset
2 ##
30564
796f54d4ddbf update Octave Project Developers copyright for the new year
John W. Eaton <jwe@octave.org>
parents: 29359
diff changeset
3 ## Copyright (C) 1995-2022 The Octave Project Developers
27918
b442ec6dda5c use centralized file for copyright info for individual contributors
John W. Eaton <jwe@octave.org>
parents: 26376
diff changeset
4 ##
27923
bd51beb6205e update formatting of copyright notices
John W. Eaton <jwe@octave.org>
parents: 27919
diff changeset
5 ## See the file COPYRIGHT.md in the top-level directory of this
bd51beb6205e update formatting of copyright notices
John W. Eaton <jwe@octave.org>
parents: 27919
diff changeset
6 ## distribution or <https://octave.org/copyright/>.
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3191
diff changeset
7 ##
3922
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3457
diff changeset
8 ## This file is part of Octave.
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3457
diff changeset
9 ##
24534
194eb4bd202b maint: Update punctuation for GPL v3 license text.
Rik <rik@octave.org>
parents: 23220
diff changeset
10 ## Octave is free software: you can redistribute it and/or modify it
3922
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3457
diff changeset
11 ## under the terms of the GNU General Public License as published by
24534
194eb4bd202b maint: Update punctuation for GPL v3 license text.
Rik <rik@octave.org>
parents: 23220
diff changeset
12 ## the Free Software Foundation, either version 3 of the License, or
22755
3a2b891d0b33 maint: Standardize Copyright formatting.
Rik <rik@octave.org>
parents: 22323
diff changeset
13 ## (at your option) any later version.
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3191
diff changeset
14 ##
3922
38c61cbf086c [project @ 2002-05-01 06:48:35 by jwe]
jwe
parents: 3457
diff changeset
15 ## Octave is distributed in the hope that it will be useful, but
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
16 ## WITHOUT ANY WARRANTY; without even the implied warranty of
22755
3a2b891d0b33 maint: Standardize Copyright formatting.
Rik <rik@octave.org>
parents: 22323
diff changeset
17 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
3a2b891d0b33 maint: Standardize Copyright formatting.
Rik <rik@octave.org>
parents: 22323
diff changeset
18 ## GNU General Public License for more details.
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3191
diff changeset
19 ##
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
20 ## You should have received a copy of the GNU General Public License
7016
93c65f2a5668 [project @ 2007-10-12 06:40:56 by jwe]
jwe
parents: 6547
diff changeset
21 ## along with Octave; see the file COPYING. If not, see
24534
194eb4bd202b maint: Update punctuation for GPL v3 license text.
Rik <rik@octave.org>
parents: 23220
diff changeset
22 ## <https://www.gnu.org/licenses/>.
27923
bd51beb6205e update formatting of copyright notices
John W. Eaton <jwe@octave.org>
parents: 27919
diff changeset
23 ##
bd51beb6205e update formatting of copyright notices
John W. Eaton <jwe@octave.org>
parents: 27919
diff changeset
24 ########################################################################
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
25
3449
858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe]
jwe
parents: 3426
diff changeset
26 ## -*- texinfo -*-
20852
516bb87ea72e 2015 Code Sprint: remove class of function from docstring for all m-files.
Rik <rik@octave.org>
parents: 20231
diff changeset
27 ## @deftypefn {} {@var{y} =} stft (@var{x})
516bb87ea72e 2015 Code Sprint: remove class of function from docstring for all m-files.
Rik <rik@octave.org>
parents: 20231
diff changeset
28 ## @deftypefnx {} {@var{y} =} stft (@var{x}, @var{win_size})
516bb87ea72e 2015 Code Sprint: remove class of function from docstring for all m-files.
Rik <rik@octave.org>
parents: 20231
diff changeset
29 ## @deftypefnx {} {@var{y} =} stft (@var{x}, @var{win_size}, @var{inc})
516bb87ea72e 2015 Code Sprint: remove class of function from docstring for all m-files.
Rik <rik@octave.org>
parents: 20231
diff changeset
30 ## @deftypefnx {} {@var{y} =} stft (@var{x}, @var{win_size}, @var{inc}, @var{num_coef})
516bb87ea72e 2015 Code Sprint: remove class of function from docstring for all m-files.
Rik <rik@octave.org>
parents: 20231
diff changeset
31 ## @deftypefnx {} {@var{y} =} stft (@var{x}, @var{win_size}, @var{inc}, @var{num_coef}, @var{win_type})
516bb87ea72e 2015 Code Sprint: remove class of function from docstring for all m-files.
Rik <rik@octave.org>
parents: 20231
diff changeset
32 ## @deftypefnx {} {[@var{y}, @var{c}] =} stft (@dots{})
9072
bd8e388043c4 Cleanup documentation for signal.texi, image.texi, audio.texi
Rik <rdrider0-list@yahoo.com>
parents: 8920
diff changeset
33 ## Compute the short-time Fourier transform of the vector @var{x} with
3449
858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe]
jwe
parents: 3426
diff changeset
34 ## @var{num_coef} coefficients by applying a window of @var{win_size} data
858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe]
jwe
parents: 3426
diff changeset
35 ## points and an increment of @var{inc} points.
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
36 ##
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
37 ## Before computing the Fourier transform, one of the following windows
3449
858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe]
jwe
parents: 3426
diff changeset
38 ## is applied:
858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe]
jwe
parents: 3426
diff changeset
39 ##
858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe]
jwe
parents: 3426
diff changeset
40 ## @table @asis
17718
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
41 ## @item @qcode{"hanning"}
11469
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
42 ## win_type = 1
10821
693e22af08ae Grammarcheck documentation of m-files
Rik <octave@nomad.inbox5.com>
parents: 10791
diff changeset
43 ##
17718
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
44 ## @item @qcode{"hamming"}
11469
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
45 ## win_type = 2
10821
693e22af08ae Grammarcheck documentation of m-files
Rik <octave@nomad.inbox5.com>
parents: 10791
diff changeset
46 ##
17718
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
47 ## @item @qcode{"rectangle"}
11469
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
48 ## win_type = 3
3449
858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe]
jwe
parents: 3426
diff changeset
49 ## @end table
858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe]
jwe
parents: 3426
diff changeset
50 ##
11469
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
51 ## The window names can be passed as strings or by the @var{win_type} number.
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
52 ##
17754
dffb1e9a6d3b doc: Final spellcheck of documentation before 3.8 release.
Rik <rik@octave.org>
parents: 17744
diff changeset
53 ## The following defaults are used for unspecified arguments:
3449
858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe]
jwe
parents: 3426
diff changeset
54 ## @var{win_size} = 80, @var{inc} = 24, @var{num_coef} = 64, and
11469
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
55 ## @var{win_type} = 1.
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
56 ##
20165
f1d0f506ee78 doc: Update more docstrings to have one sentence summary as first line.
Rik <rik@octave.org>
parents: 19697
diff changeset
57 ## @code{@var{y} = stft (@var{x}, @dots{})} returns the absolute values of the
f1d0f506ee78 doc: Update more docstrings to have one sentence summary as first line.
Rik <rik@octave.org>
parents: 19697
diff changeset
58 ## Fourier coefficients according to the @var{num_coef} positive frequencies.
3449
858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe]
jwe
parents: 3426
diff changeset
59 ##
25472
9771111f04f4 doc: Use @var rather than @code to mark inputs to functions in docstrings.
Rik <rik@octave.org>
parents: 25054
diff changeset
60 ## @code{[@var{y}, @var{c}] = stft (@var{x}, @dots{})} returns the entire
20165
f1d0f506ee78 doc: Update more docstrings to have one sentence summary as first line.
Rik <rik@octave.org>
parents: 19697
diff changeset
61 ## STFT-matrix @var{y} and a 3-element vector @var{c} containing the window
f1d0f506ee78 doc: Update more docstrings to have one sentence summary as first line.
Rik <rik@octave.org>
parents: 19697
diff changeset
62 ## size, increment, and window type, which is needed by the @code{synthesis}
f1d0f506ee78 doc: Update more docstrings to have one sentence summary as first line.
Rik <rik@octave.org>
parents: 19697
diff changeset
63 ## function.
17718
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
64 ## @seealso{synthesis}
3449
858695b3ed62 [project @ 2000-01-18 04:08:59 by jwe]
jwe
parents: 3426
diff changeset
65 ## @end deftypefn
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
66
17718
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
67 function [y, c] = stft (x, win_size = 80, inc = 24, num_coef = 64, win_type = 1)
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3191
diff changeset
68
28789
28de41192f3c Eliminate unneeded verification of nargin, nargout in m-files.
Rik <rik@octave.org>
parents: 27984
diff changeset
69 if (nargin < 1)
6046
34f96dd5441b [project @ 2006-10-10 16:10:25 by jwe]
jwe
parents: 5443
diff changeset
70 print_usage ();
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
71 endif
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
72
17718
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
73 if (ischar (win_type))
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
74 switch (tolower (win_type))
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
75 case "hanning" win_type = 1;
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
76 case "hamming" win_type = 2;
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
77 case "rectangle" win_type = 3;
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
78 otherwise
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
79 error ("stft: unknown window type '%s'", win_type);
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
80 endswitch
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
81 endif
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
82
8506
bc982528de11 comment style fixes
John W. Eaton <jwe@octave.org>
parents: 7017
diff changeset
83 ## Check whether X is a vector.
17718
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
84 if (! isvector (x))
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
85 error ("stft: X must be a vector");
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
86 endif
17718
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
87 x = x(:);
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
88
11469
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
89 ncoef = 2 * num_coef;
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
90 if (win_size > ncoef)
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
91 win_size = ncoef;
21634
96518f623c91 Backed out changeset dcf8922b724b
Mike Miller <mtmiller@octave.org>
parents: 21633
diff changeset
92 printf ("stft: window size adjusted to %f\n", win_size);
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
93 endif
17718
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
94 num_win = fix ((rows (x) - win_size) / inc);
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
95
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
96 ## compute the window coefficients
17718
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
97 switch (win_type)
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
98 case 1 win_coef = hanning (win_size);
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
99 case 2 win_coef = hamming (win_size);
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
100 case 3 win_coef = ones (win_size, 1);
6ed0a8532bcf Overhaul stft and synthesis functions
Rik <rik@octave.org>
parents: 17338
diff changeset
101 endswitch
3426
f8dde1807dee [project @ 2000-01-13 08:40:00 by jwe]
jwe
parents: 3191
diff changeset
102
8506
bc982528de11 comment style fixes
John W. Eaton <jwe@octave.org>
parents: 7017
diff changeset
103 ## Create a matrix Z whose columns contain the windowed time-slices.
11469
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
104 z = zeros (ncoef, num_win + 1);
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
105 start = 1;
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
106 for i = 0:num_win
11469
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
107 z(1:win_size, i+1) = x(start:start+win_size-1) .* win_coef;
20231
83792dd9bcc1 Use in-place operators in m-files where possible.
Rik <rik@octave.org>
parents: 20165
diff changeset
108 start += inc;
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
109 endfor
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
110
11469
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
111 y = fft (z);
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
112
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
113 if (nargout == 1)
11469
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
114 y = abs (y(1:num_coef, :));
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
115 else
11469
c776f063fefe Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents: 10821
diff changeset
116 c = [win_size, inc, win_type];
3191
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
117 endif
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
118
e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
jwe
parents:
diff changeset
119 endfunction