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1 ## Copyright (C) 1996, 1998 Auburn University. All rights reserved. |
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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 the |
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7 ## Free Software Foundation; either version 2, or (at your option) any |
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8 ## later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but WITHOUT |
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11 ## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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12 ## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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13 ## 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, write to the Free |
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17 ## Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Function File } { @var{sys} =} zp2sys (@var{zer},@var{pol},@var{k}@{,@var{tsam},@var{inname},@var{outname}@}) |
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21 ## Create system data structure from zero-pole data |
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22 ## |
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23 ## @strong{Inputs} |
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24 ## @table @var |
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25 ## @item zer |
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26 ## vector of system zeros |
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27 ## @item pol |
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28 ## vector of system poles |
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29 ## @item k |
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30 ## scalar leading coefficient |
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31 ## @item tsam |
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32 ## sampling period. default: 0 (continuous system) |
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33 ## @item inname |
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34 ## @itemx outname |
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35 ## input/output signal names (lists of strings) |
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36 ## @end table |
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37 ## |
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38 ## @strong{Outputs} |
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39 ## sys: system data structure |
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40 ## |
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41 ## @strong{Example} |
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42 ## @example |
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43 ## octave:1> sys=zp2sys([1 -1],[-2 -2 0],1); |
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44 ## octave:2> sysout(sys) |
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45 ## Input(s) |
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46 ## 1: u_1 |
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47 ## Output(s): |
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48 ## 1: y_1 |
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49 ## zero-pole form: |
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50 ## 1 (s - 1) (s + 1) |
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51 ## ----------------- |
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52 ## s (s + 2) (s + 2) |
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53 ## @end example |
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54 ## @end deftypefn |
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55 |
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56 ## Modified by John Ingram July 20, 1996 |
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57 |
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58 function outsys = zp2sys (zer, pol, k, tsam, inname, outname) |
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59 |
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60 ## Test for the correct number of input arguments |
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61 if ((nargin < 3) || (nargin > 6)) |
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62 usage("outsys = zp2sys(zer,pol,k[,tsam,inname,outname])"); |
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63 endif |
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64 |
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65 ## check input format |
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66 if( ! (is_vector(zer) | isempty(zer) ) ) |
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67 error("zer must be a vector or empty"); |
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68 endif |
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69 if(!isempty(zer)) |
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70 zer = reshape(zer,1,length(zer)); # make it a row vector |
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71 endif |
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72 |
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73 if( ! (is_vector(pol) | isempty(pol))) |
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74 error("pol must be a vector"); |
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75 endif |
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76 if(!isempty(pol)) |
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77 pol = reshape(pol,1,length(pol)); |
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78 endif |
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79 |
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80 if (! is_scalar(k)) |
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81 error("k must be a scalar"); |
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82 endif |
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83 |
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84 ## Test proper numbers of poles and zeros. The number of poles must be |
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85 ## greater than or equal to the number of zeros. |
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86 if (length(zer) > length(pol)) |
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87 error(["number of poles (", num2str(length(pol)), ... |
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88 ") < number of zeros (", num2str(length(zer)),")"]); |
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89 endif |
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90 |
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91 ## Set the system transfer function |
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92 outsys.zer = zer; |
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93 outsys.pol = pol; |
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94 outsys.k = k; |
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95 |
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96 ## Set the system vector: active = 1, updated = [0 1 0]; |
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97 outsys.sys = [1, 0, 1, 0]; |
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98 |
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99 ## Set defaults |
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100 outsys.tsam = 0; |
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101 outsys.n = length(pol); |
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102 outsys.nz = 0; |
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103 outsys.yd = 0; # assume (for now) continuous time outputs |
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104 |
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105 ## Set the type of system |
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106 if (nargin > 3) |
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107 if( !is_scalar(tsam) ) |
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108 error("tsam must be a nonnegative scalar"); |
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109 endif |
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110 if (tsam < 0) |
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111 error("sampling time must be positve") |
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112 elseif (tsam > 0) |
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113 [outsys.n,outsys.nz] = swap(outsys.n, outsys.nz); |
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114 outsys.yd = 1; # discrete-time output |
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115 endif |
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116 |
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117 outsys.tsam = tsam; |
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118 endif |
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119 |
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120 outsys.inname = sysdefioname(1,"u"); |
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121 outsys.outname = sysdefioname(1,"y"); |
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122 outsys.stname = sysdefstname(outsys.n,outsys.nz); |
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123 |
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124 ## Set name of input |
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125 if (nargin > 4) |
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126 ## make sure its a string |
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127 if(!isempty(inname)) |
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128 if(!is_list(inname)) inname = list(inname); endif |
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129 if(!is_signal_list(inname)) |
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130 error("inname must be a single signal name"); |
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131 endif |
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132 outsys.inname = inname(1); |
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133 endif |
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134 endif |
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135 |
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136 ## Set name of output |
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137 if (nargin > 5) |
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138 if(!isempty(outname)) |
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139 if(!is_list(outname)) outname = list(outname); endif |
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140 if(!is_signal_list(outname)) |
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141 error("outname must be a single signal name"); |
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142 endif |
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143 outsys.outname = outname(1); |
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144 endif |
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145 endif |
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146 |
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147 endfunction |
