1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
## Copyright (C) 2002 John W. Eaton
##
## This file is part of Octplot
##
## 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 2, 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, write to the Free
## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
## 02111-1307, USA.
## -*- texinfo -*-
## @deftypefn {Function File} freqz_plot (@var{w}, @var{h})
## Plot the pass band, stop band and phase response of @var{h}.
## @end deftypefn
## Author: Paul Kienzle <pkienzle@users.sf.net>
## Author: Adapted for octplot by Shai Ayal
## adaptation to octplot was mainly by changing the order of the
## axis and plot commands since the plot commands reset the axis
function freqz_plot(w,h)
n = length (w);
mag = 20 * log10 (abs (h));
phase = unwrap (arg (h));
maxmag = max (mag);
subplot (3,1,1);
grid ("on");
title("Pass Band (dB)");
plot (w, mag);
axis ([ w(1), w(n), maxmag-3, maxmag ]);
subplot (3,1,2);
grid ("on");
title("Stop Band (dB)");
plot (w, mag, ";Stop band (dB);");
if (maxmag - min (mag) > 100)
axis ([ w(1), w(n), maxmag-100, maxmag ]);
else
set(gca(),"YLimMode","auto");
endif
subplot (3,1,3);
grid("on");
xlabel ("Frequency");
title("Phase (degrees)");
plot (w, phase*360/(2*pi), ";Phase (degrees);");
axis ([ w(1), w(n) ]);
endfunction
|
