why the bode function doesn't work?

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jia ming chen
jia ming chen on 19 Jan 2015
Answered: Felix Götze on 9 Feb 2016
this is my problem...
>> s=tf('s')
s =
Continuous-time transfer function.
>> g=1/(1+s)
g =
s + 1
Continuous-time transfer function.
>> bode(g) Error using DynamicSystem/bode (line 97) Index exceeds matrix dimensions.
can anyone solve it?

Answers (3)

Felix Götze
Felix Götze on 9 Feb 2016
I had the same Problem. In my case the error occured because I had a figure window open. If you have an open figure close it and try the command again it should work properly now.

Youssef  Khmou
Youssef Khmou on 19 Jan 2015
Edited: Youssef Khmou on 19 Jan 2015
The description is correct and the code is working correctly,try clearing the existing variables
clear all;
s=tf('s'); g=1/(1+s); bode(g);
Youssef  Khmou
Youssef Khmou on 20 Jan 2015
Edited: Youssef Khmou on 20 Jan 2015
Bode function contains the following code from line 92 through 100
92 case 3
93 % Transfer function form with time vector
94 if size(a,1)>1,
95 % SIMO syntax
96 a = num2cell(a,2);
97 den = b;
98 b = cell(size(a,1),1);
99 b(:) = {den};
100 end

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Andreas Goser
Andreas Goser on 20 Jan 2015
Can you verify the output of
which bode -all
Youe should get something like this:
C:\Program Files\MATLAB\R2014b\toolbox\control\ctrlobsolete\bode.m
C:\Program Files\MATLAB\R2014b\toolbox\shared\controllib\engine\@DynamicSystem\bode.m % DynamicSystem method
Is not, there maybe another function or variable shadowing the bode function you want.
Andreas Goser
Andreas Goser on 19 Mar 2015
This user had a different error message. The solution was a compatibility with a 3rd part toolbox. Once this was removed from the path, BODE was working fine.

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