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
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
## Copyright (C) 1996, 1998, 2000, 2002, 2004, 2005, 2007
## Auburn University. All rights reserved.
##
##
## This program 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 3 of the License, or (at
## your option) any later version.
##
## This program 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 this program; see the file COPYING. If not, see
## <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @deftypefn {Function File} {[@var{num}, @var{den}] =} zp2tf (@var{zer}, @var{pol}, @var{k})
## Converts zeros / poles to a transfer function.
##
## @strong{Inputs}
## @table @var
## @item zer
## @itemx pol
## Vectors of (possibly complex) poles and zeros of a transfer
## function. Complex values must appear in conjugate pairs.
## @item k
## Real scalar (leading coefficient).
## @end table
## @end deftypefn
## Author: A. S. Hodel <a.s.hodel@eng.auburn.edu>
## (With help from students Ingram, McGowan.)
function [num, den] = zp2tf (zer, pol, k)
if (nargin != 3)
print_usage ();
endif
## Find out whether data was entered as a row or a column vector and
## convert to a column vector if necessary.
[rp, cp] = size (pol);
[rz, cz] = size (zer);
if (! (isvector (zer) || isempty (zer)))
error ("zer(%dx%d) must be a vector", rz, cz);
elseif (! (isvector (pol) || isempty (pol)))
error ("pol(%dx%d) must be a vector", rp, cp);
elseif (length (zer) > length (pol))
error ("zer(%dx%d) longer than pol(%dx%d)", rz, cz, rp, cp);
endif
## initialize converted polynomials
num = k;
den = 1;
## call __zp2ssg2__ if there are complex conjugate pairs left, otherwise
## construct real zeros one by one. Repeat for poles.
while (! isempty (zer))
if (max (abs (imag (zer))))
[poly, zer] = __zp2ssg2__ (zer);
else
poly = [1, -zer(1)];
zer = zer(2:length(zer));
endif
num = conv (num, poly);
endwhile
while (! isempty (pol))
if (max (abs (imag (pol))))
[poly, pol] = __zp2ssg2__ (pol);
else
poly = [1, -pol(1)];
pol = pol(2:length(pol));
endif
den = conv (den, poly);
endwhile
endfunction
|
