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1 ## Copyright (C) 1996, 1998, 2004, 2005, 2006, 2007 |
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2 ## Auburn University. All rights reserved. |
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3 ## |
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4 ## This file is part of Octave. |
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5 ## |
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6 ## Octave is free software; you can redistribute it and/or modify it |
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7 ## under the terms of the GNU General Public License as published by |
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8 ## the Free Software Foundation; either version 3 of the License, or (at |
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9 ## your option) any later version. |
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10 ## |
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11 ## Octave is distributed in the hope that it will be useful, but |
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12 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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14 ## General Public License for more details. |
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15 ## |
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16 ## You should have received a copy of the GNU General Public License |
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17 ## along with Octave; see the file COPYING. If not, see |
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18 ## <http://www.gnu.org/licenses/>. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} zp (@var{zer}, @var{pol}, @var{k}, @var{tsam}, @var{inname}, @var{outname}) |
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22 ## Create system data structure from zero-pole data. |
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23 ## |
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24 ## @strong{Inputs} |
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25 ## @table @var |
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26 ## @item zer |
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27 ## vector of system zeros |
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28 ## @item pol |
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29 ## vector of system poles |
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30 ## @item k |
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31 ## scalar leading coefficient |
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32 ## @item tsam |
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33 ## sampling period. default: 0 (continuous system) |
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34 ## @item inname |
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35 ## @itemx outname |
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36 ## input/output signal names (lists of strings) |
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37 ## @end table |
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38 ## |
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39 ## @strong{Outputs} |
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40 ## sys: system data structure |
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41 ## |
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42 ## @strong{Example} |
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43 ## @example |
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44 ## octave:1> sys=zp([1 -1],[-2 -2 0],1); |
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45 ## octave:2> sysout(sys) |
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46 ## Input(s) |
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47 ## 1: u_1 |
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48 ## Output(s): |
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49 ## 1: y_1 |
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50 ## zero-pole form: |
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51 ## 1 (s - 1) (s + 1) |
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52 ## ----------------- |
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53 ## s (s + 2) (s + 2) |
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54 ## @end example |
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55 ## @end deftypefn |
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56 |
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57 ## Modified by John Ingram July 20, 1996 |
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58 |
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59 function outsys = zp (zer, pol, k, tsam, inname, outname) |
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60 |
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61 ## Test for the correct number of input arguments |
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62 if (nargin < 3 || nargin > 6) |
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63 print_usage (); |
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64 endif |
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65 |
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66 ## check input format |
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67 if (! (isvector (zer) || isempty (zer))) |
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68 error ("zer must be a vector or empty"); |
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69 endif |
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70 if (! isempty (zer)) |
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71 zer = reshape (zer, 1, length (zer)); # make it a row vector |
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72 endif |
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73 |
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74 if (! (isvector (pol) || isempty (pol))) |
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75 error ("pol must be a vector"); |
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76 endif |
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77 if (! isempty (pol)) |
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78 pol = reshape (pol, 1, length (pol)); |
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79 endif |
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80 |
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81 if (! isscalar (k)) |
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82 error ("k must be a scalar"); |
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83 endif |
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84 |
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85 ## Test proper numbers of poles and zeros. The number of poles must be |
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86 ## greater than or equal to the number of zeros. |
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87 if (length (zer) > length (pol)) |
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88 error ("number of poles (%d) < number of zeros (%d)", |
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89 length (pol), length (zer)); |
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90 endif |
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91 |
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92 ## Set the system transfer function |
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93 outsys.zer = zer; |
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94 outsys.pol = pol; |
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95 outsys.k = k; |
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96 |
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97 ## Set the system vector: active = 1, updated = [0 1 0]; |
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98 outsys.sys = [1, 0, 1, 0]; |
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99 |
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100 ## Set defaults |
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101 outsys.tsam = 0; |
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102 outsys.n = length (pol); |
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103 outsys.nz = 0; |
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104 outsys.yd = 0; # assume (for now) continuous time outputs |
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105 |
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106 ## Set the type of system |
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107 if (nargin > 3) |
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108 if (! isscalar (tsam)) |
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109 error ("tsam must be a nonnegative scalar"); |
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110 endif |
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111 if (tsam < 0) |
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112 error ("sampling time must be positve") |
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113 elseif (tsam > 0) |
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114 [outsys.n, outsys.nz] = swap (outsys.n, outsys.nz); |
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115 outsys.yd = 1; # discrete-time output |
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116 endif |
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117 |
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118 outsys.tsam = tsam; |
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119 endif |
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120 |
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121 outsys.inname = __sysdefioname__ (1, "u"); |
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122 outsys.outname = __sysdefioname__ (1, "y"); |
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123 outsys.stname = __sysdefstname__ (outsys.n, outsys.nz); |
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124 |
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125 ## Set name of input |
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126 if (nargin > 4) |
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127 ## make sure its a string |
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128 if (! isempty (inname)) |
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129 if (! iscell (inname)) |
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130 inname = {inname}; |
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131 endif |
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132 if (! is_signal_list (inname)) |
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133 error ("inname must be a single signal name"); |
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134 endif |
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135 outsys.inname = inname(1); |
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136 endif |
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137 endif |
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138 |
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139 ## Set name of output |
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140 if (nargin > 5) |
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141 if (! isempty (outname)) |
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142 if (! iscell (outname)) |
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143 outname = {outname}; |
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144 endif |
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145 if (! is_signal_list (outname)) |
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146 error ("outname must be a single signal name"); |
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147 endif |
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148 outsys.outname = outname(1); |
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149 endif |
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150 endif |
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151 |
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152 endfunction |
