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comparison scripts/signal/freqz_plot.m @ 3942:2ca2d23a49a7

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[project @ 2002-05-16 20:27:59 by jwe]
author jwe
date Thu, 16 May 2002 20:28:17 +0000
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children 8aa604426d35
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3941:fab8337340a1 3942:2ca2d23a49a7
1 ## Copyright (C) 2002 John W. Eaton
2 ##
3 ## This file is part of Octave.
4 ##
5 ## Octave is free software; you can redistribute it and/or modify it
6 ## under the terms of the GNU General Public License as published by
7 ## the Free Software Foundation; either version 2, or (at your option)
8 ## any later version.
9 ##
10 ## Octave is distributed in the hope that it will be useful, but
11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 ## General Public License for more details.
14 ##
15 ## You should have received a copy of the GNU General Public License
16 ## along with Octave; see the file COPYING. If not, write to the Free
17 ## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
18 ## 02111-1307, USA.
19
20 ## -*- texinfo -*-
21 ## @deftypefn {Function File} freqz_plot (@var{w}, @var{h})
22 ## Plot the pass band, stop band and phase response of @var{h}.
23 ## @end deftypefn
24
25 ## Author: Paul Kienzle <pkienzle@users.sf.net>
26
27 function freqz_plot(w,h)
28
29 n = length (w);
30
31 ## ## exclude zero-frequency
32 ## h = h (2 : length (h));
33 ## w = w (2 : length (w));
34 ## n = n-1;
35
36 mag = 20 * log10 (abs (h));
37 phase = unwrap (arg (h));
38 maxmag = max (mag);
39
40 unwind_protect
41
42 ## Protect graph state.
43
44 if (gnuplot_has_multiplot)
45 subplot (311);
46 gset lmargin 10;
47 axis ("labely");
48 xlabel ("");
49 endif
50 grid ("on");
51 axis ([ w(1), w(n), maxmag-3, maxmag ]);
52 plot (w, mag, ";Pass band (dB);");
53
54 if (gnuplot_has_multiplot)
55 subplot (312);
56 axis ("labely");
57 title ("");
58 xlabel ("");
59 gset tmargin 0;
60 else
61 input ("press any key for the next plot: ");
62 endif
63 grid ("on");
64 if (maxmag - min (mag) > 100)
65 axis ([ w(1), w(n), maxmag-100, maxmag ]);
66 else
67 axis ("autoy");
68 endif
69 plot (w, mag, ";Stop band (dB);");
70
71 if (gnuplot_has_multiplot)
72 subplot (313);
73 axis ("label");
74 title ("");
75 else
76 input ("press any key for the next plot: ");
77 endif
78 grid ("on");
79 axis ("autoy");
80 xlabel ("Frequency");
81 axis ([ w(1), w(n) ]);
82 plot (w, phase/(2*pi), ";Phase (radians/2pi);");
83
84 unwind_protect_cleanup
85
86 ## Restore graph state.
87
88 ## XXX FIXME XXX -- if automatic_replot is non-zero, this will
89 ## mess up the graph, however if we don't do it here then the user
90 ## will have to do it themselves.
91
92 grid ("off");
93 axis ("auto", "label");
94 gset lmargin;
95 gset tmargin;
96 oneplot ();
97
98 end_unwind_protect
99
100 endfunction