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codesprint: 9 tests for bartlett.m
author Andriy Shinkarchuck <adriano32.gnu@gmail.com>
date Sat, 03 Sep 2011 14:09:51 -0500
parents fd0a3ac60b0e
children 984359717d71
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fd0a3ac60b0e update copyright notices
John W. Eaton <jwe@octave.org>
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1 ## Copyright (C) 1995-2011 Andreas Weingessel
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2 ##
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3 ## This file is part of Octave.
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4 ##
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5 ## Octave is free software; you can redistribute it and/or modify it
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6 ## under the terms of the GNU General Public License as published by
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7 ## the Free Software Foundation; either version 3 of the License, or (at
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8 ## your option) any later version.
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9 ##
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10 ## Octave is distributed in the hope that it will be useful, but
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 ## General Public License for more details.
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14 ##
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15 ## You should have received a copy of the GNU General Public License
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16 ## along with Octave; see the file COPYING. If not, see
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17 ## <http://www.gnu.org/licenses/>.
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18
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19 ## -*- texinfo -*-
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20 ## @deftypefn {Function File} {} blackman (@var{m})
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21 ## Return the filter coefficients of a Blackman window of length @var{m}.
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22 ##
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23 ## For a definition of the Blackman window, see e.g., A. V. Oppenheim &
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Brian Gough <bjg@gnu.org>
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24 ## R. W. Schafer, @cite{Discrete-Time Signal Processing}.
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25 ## @end deftypefn
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26
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27 ## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at>
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28 ## Description: Coefficients of the Blackman window
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29
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30 function c = blackman (m)
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31
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32 if (nargin != 1)
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33 print_usage ();
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34 endif
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35
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36 if (! (isscalar (m) && (m == round (m)) && (m > 0)))
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37 error ("blackman: M has to be an integer > 0");
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38 endif
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39
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40 if (m == 1)
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41 c = 1;
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42 else
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43 m = m - 1;
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44 k = (0 : m)' / m;
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45 c = 0.42 - 0.5 * cos (2 * pi * k) + 0.08 * cos (4 * pi * k);
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46 endif
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47
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48 endfunction
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542891ebfcdb codesprint: 9 tests for bartlett.m
Andriy Shinkarchuck <adriano32.gnu@gmail.com>
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50 %!assert (blackman (1), 1);
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51 %!assert (blackman (2), zeros(2,1), 1e-6);
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52 %!assert (blackman (16), fliplr (blackman (16)));
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53 %!assert (blackman (15), fliplr (blackman (15)));
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54 %!test
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55 %! N = 9;
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56 %! A = blackman (N);
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57 %! assert (A (ceil (N/2)), 1, 1e-6);
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58 %! assert ([A(1), A(length (A))], zeros (1, 2), 1e-6);
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59
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60 %!error blackman ();
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61 %!error blackman (0.5);
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62 %!error blackman (-1);
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63 %!error blackman (ones(1,4));