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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 |
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7 ## the Free Software Foundation; either version 3 of the License, or (at |
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8 ## your option) any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License 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, see |
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17 ## <http://www.gnu.org/licenses/>. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Function File} {[@var{zer}, @var{pol}] =} pzmap (@var{sys}) |
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21 ## Plots the zeros and poles of a system in the complex plane. |
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22 ## |
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23 ## @strong{Input} |
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24 ## @table @var |
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25 ## @item sys |
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26 ## System data structure. |
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27 ## @end table |
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28 ## |
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29 ## @strong{Outputs} |
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30 ## @table @var |
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31 ## @item pol |
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32 ## @item zer |
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33 ## if omitted, the poles and zeros are plotted on the screen. |
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34 ## otherwise, @var{pol} and @var{zer} are returned as the |
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35 ## system poles and zeros (see @command{sys2zp} for a preferable function call). |
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36 ## @end table |
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37 ## @end deftypefn |
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38 |
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39 function [zer, pol] = pzmap (sys) |
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40 |
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41 if (nargin != 1) |
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42 print_usage (); |
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43 elseif (! isstruct (sys)); |
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44 error ("pzmap: sys must be in system format"); |
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45 endif |
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46 |
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47 [zer, pol] = sys2zp (sys); |
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48 |
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49 ## force to column vectors, split into real, imaginary parts |
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50 zerdata = poldata = []; |
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51 if (length (zer)) |
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52 zer = reshape (zer, length (zer), 1); |
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53 zerdata = [real(zer(:,1)), imag(zer(:,1))]; |
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54 endif |
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55 if (length (pol)) |
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56 pol = reshape (pol, length (pol), 1); |
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57 poldata = [real(pol(:,1)), imag(pol(:,1))]; |
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58 endif |
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59 |
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60 ## determine continuous or discrete plane |
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61 vars = "sz"; |
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62 varstr = vars(is_digital (sys) + 1); |
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63 |
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64 ## Plot the data |
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65 |
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66 if (length (zer) == 0) |
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67 plot (poldata(:,1), poldata(:,2), "@12 ;poles (no zeros);"); |
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68 elseif (length (pol) == 0) |
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69 plot (zerdata(:,1), zerdata(:,2), "@31 ;zeros (no poles);"); |
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70 else |
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71 plot (zerdata(:,1), zerdata(:,2), "@31 ;zeros;", |
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72 poldata(:,1), poldata(:,2), "@12 ;poles;"); |
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73 endif |
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74 |
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75 if (is_siso (sys)) |
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76 title (sprintf ("Pole-zero map from %s to %s", |
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77 sysgetsignals (sys, "in", 1, 1), |
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78 sysgetsignals (sys, "out", 1, 1))); |
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79 endif |
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80 |
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81 xlabel (sprintf ("Re(%s)", varstr)); |
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82 ylabel (sprintf ("Im(%s)", varstr)); |
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83 grid ("on"); |
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84 |
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85 ## compute axis limits |
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86 axis (axis2dlim ([zerdata; poldata])); |
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87 |
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88 endfunction |
