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comparison scripts/control/bode.m @ 3282:518ea57df2c4

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[project @ 1999-10-13 19:00:38 by jwe]
author jwe
date Wed, 13 Oct 1999 19:00:38 +0000
parents 6dd06d525de6
children f7e4a95916f2
comparison
equal deleted inserted replaced
3281:aaaa20d31a5f 3282:518ea57df2c4
14 # 14 #
15 # You should have received a copy of the GNU General Public License 15 # You should have received a copy of the GNU General Public License
16 # along with Octave; see the file COPYING. If not, write to the Free 16 # along with Octave; see the file COPYING. If not, write to the Free
17 # Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. 17 # Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
18 18
19 function [mag,phase,w] = bode(sys,w,outputs,inputs) 19 function [mag,phase,w] = bode(sys,w,outputs,inputs,plot_style)
20 # [mag,phase,w] = bode(sys[,w,outputs,inputs]) 20 # [mag,phase,w] = bode(sys[,w,outputs,inputs,plot_style])
21 # Produce Bode plots of a system 21 # Produce Bode plots of a system
22 # 22 #
23 # Compute the frequency response of a system. 23 # Compute the frequency response of a system.
24 # inputs: 24 # inputs:
25 # sys: system data structure (must be either purely continuous or discrete; 25 # sys: system data structure (must be either purely continuous or discrete;
38 # (3) A "smoothing" routine is used to ensure that the plot phase does 38 # (3) A "smoothing" routine is used to ensure that the plot phase does
39 # not change excessively from point to point and that singular 39 # not change excessively from point to point and that singular
40 # points (e.g., crossovers from +/- 180) are accurately shown. 40 # points (e.g., crossovers from +/- 180) are accurately shown.
41 # outputs, inputs: the indices of the output(s) and input(s) to be used in 41 # outputs, inputs: the indices of the output(s) and input(s) to be used in
42 # the frequency response; see sysprune. 42 # the frequency response; see sysprune.
43 # plot_style: An optional argument specifying the type of plot to
44 # produce (if plotting is being done). Valid values are
45 # "dB" or "mag". If omitted, "dB" is assumed.
46 #
43 # outputs: 47 # outputs:
44 # mag, phase: the magnitude and phase of the frequency response 48 # mag, phase: the magnitude and phase of the frequency response
45 # G(jw) or G(exp(jwT)) at the selected frequency values. 49 # G(jw) or G(exp(jwT)) at the selected frequency values.
46 # w: the vector of frequency values used 50 # w: the vector of frequency values used
47 # If no output arguments are given, bode plots the results to the screen. 51 # If no output arguments are given, bode plots the results to the screen.
57 # Modified by David Clem November 13, 1994 61 # Modified by David Clem November 13, 1994
58 # again by A. S. Hodel July 1995 (smart plot range, etc.) 62 # again by A. S. Hodel July 1995 (smart plot range, etc.)
59 # Modified by Kai P. Mueller September 28, 1997 (multiplot mode) 63 # Modified by Kai P. Mueller September 28, 1997 (multiplot mode)
60 64
61 # check number of input arguments given 65 # check number of input arguments given
62 if (nargin < 1 | nargin > 4) 66 if (nargin < 1 | nargin > 5)
63 usage("[mag,phase,w] = bode(sys[,w,outputs,inputs])"); 67 usage("[mag,phase,w] = bode(sys[,w,outputs,inputs,plot_style])");
64 endif 68 endif
65 if(nargin < 2) 69 if(nargin < 2)
66 w = []; 70 w = [];
67 endif 71 endif
68 if(nargin < 3) 72 if(nargin < 3)
69 outputs = []; 73 outputs = [];
70 endif 74 endif
71 if(nargin < 4) 75 if(nargin < 4)
72 inputs = []; 76 inputs = [];
77 endif
78 if(nargin < 5)
79 plot_style = "dB";
80 endif
81
82 if (strcmp (plot_style, "dB"))
83 do_db_plot = 1;
84 elseif (strcmp (plot_style, "mag"))
85 do_db_plot = 0;
86 else
87 error ("bode: invalid value of plot_style specified");
73 endif 88 endif
74 89
75 [f, w] = bodquist(sys,w,outputs,inputs,"bode"); 90 [f, w] = bodquist(sys,w,outputs,inputs,"bode");
76 91
77 [stname,inname,outname] = sysgetsignals(sys); 92 [stname,inname,outname] = sysgetsignals(sys);
111 disp(outlist(inname," ")); 126 disp(outlist(inname," "));
112 disp("to") 127 disp("to")
113 disp(outlist(outname," ")); 128 disp(outlist(outname," "));
114 endif 129 endif
115 wv = [min(w), max(w)]; 130 wv = [min(w), max(w)];
116 if(max(mag) > 0) 131 if(do_db_plot && max(mag) > 0)
117 ylabel("Gain in dB"); 132 ylabel("Gain in dB");
118 md = 20*log10(mag); 133 md = 20*log10(mag);
119 else 134 else
120 ylabel("Gain |Y/U|") 135 ylabel("Gain |Y/U|")
121 md = mag; 136 md = mag;
123 138
124 axvec = axis2dlim([vec(w),vec(md)]); 139 axvec = axis2dlim([vec(w),vec(md)]);
125 axvec(1:2) = wv; 140 axvec(1:2) = wv;
126 axis(axvec); 141 axis(axvec);
127 grid("on"); 142 grid("on");
128 semilogx(w,md); 143 if (do_db_plot)
144 semilogx(w,md);
145 else
146 loglog(w,md);
147 endif
129 if (is_siso(sys)) 148 if (is_siso(sys))
130 if (gnuplot_has_multiplot) 149 if (gnuplot_has_multiplot)
131 subplot(2,1,2); 150 subplot(2,1,2);
132 else 151 else
133 prompt('Press any key for phase plot'); 152 prompt('Press any key for phase plot');