Mercurial > hg > octave-lyh
annotate scripts/signal/spectral_xdf.m @ 7540:3422f39573b1
strcat.m: Matlab compatibility, with cstrcat.m replacing conventional strcat.m.
| author | Ben Abbott <bpabbott@mac.com> |
|---|---|
| date | Thu, 28 Feb 2008 02:41:19 -0500 |
| parents | a1dbe9d80eee |
| children | eb63fbe60fab |
| rev | line source |
|---|---|
| 7017 | 1 ## Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2005, |
| 2 ## 2007 Friedrich Leisch | |
| 3426 | 3 ## |
| 3922 | 4 ## This file is part of Octave. |
| 5 ## | |
| 6 ## Octave is free software; you can redistribute it and/or modify it | |
| 7 ## under the terms of the GNU General Public License as published by | |
| 7016 | 8 ## the Free Software Foundation; either version 3 of the License, or (at |
| 9 ## your option) any later version. | |
| 3426 | 10 ## |
| 3922 | 11 ## Octave is distributed in the hope that it will be useful, but |
| 3191 | 12 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 3426 | 14 ## General Public License for more details. |
| 15 ## | |
| 3191 | 16 ## You should have received a copy of the GNU General Public License |
| 7016 | 17 ## along with Octave; see the file COPYING. If not, see |
| 18 ## <http://www.gnu.org/licenses/>. | |
| 3191 | 19 |
| 3449 | 20 ## -*- texinfo -*- |
| 21 ## @deftypefn {Function File} {} spectral_xdf (@var{x}, @var{win}, @var{b}) | |
| 22 ## Return the spectral density estimator given a data vector @var{x}, | |
| 23 ## window name @var{win}, and bandwidth, @var{b}. | |
| 3426 | 24 ## |
| 3449 | 25 ## The window name, e.g., @code{"triangle"} or @code{"rectangle"} is |
| 26 ## used to search for a function called @code{@var{win}_sw}. | |
| 3426 | 27 ## |
| 3449 | 28 ## If @var{win} is omitted, the triangle window is used. If @var{b} is |
| 29 ## omitted, @code{1 / sqrt (length (@var{x}))} is used. | |
| 30 ## @end deftypefn | |
| 3426 | 31 |
| 3457 | 32 ## Author: FL <Friedrich.Leisch@ci.tuwien.ac.at> |
| 33 ## Description: Spectral density estimation | |
| 3426 | 34 |
| 3191 | 35 function retval = spectral_xdf (X, win, b) |
| 3426 | 36 |
| 3191 | 37 xr = length (X); |
| 3426 | 38 |
| 3191 | 39 if (columns (X) > 1) |
| 40 X = X'; | |
| 41 endif | |
| 3426 | 42 |
| 3191 | 43 if (nargin < 3) |
| 44 b = 1 / ceil (sqrt (xr)); | |
| 45 endif | |
| 3426 | 46 |
| 3191 | 47 if (nargin == 1) |
| 48 w = triangle_sw (xr, b); | |
| 49 else | |
|
7540
3422f39573b1
strcat.m: Matlab compatibility, with cstrcat.m replacing conventional strcat.m.
Ben Abbott <bpabbott@mac.com>
parents:
7017
diff
changeset
|
50 win = str2func (cstrcat (win, "_sw")); |
| 3191 | 51 w = feval (win, xr, b); |
| 52 endif | |
| 3426 | 53 |
| 3191 | 54 X = X - sum (X) / xr; |
| 55 | |
| 56 retval = (abs (fft (X)) / xr).^2; | |
| 57 retval = real (ifft (fft(retval) .* fft(w))); | |
| 3426 | 58 |
| 3238 | 59 retval = [(zeros (xr, 1)), retval]; |
| 3191 | 60 retval(:, 1) = (0 : xr-1)' / xr; |
| 3426 | 61 |
| 3191 | 62 endfunction |
| 63 | |
| 64 | |
| 65 | |
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