why the bode function doesn't work?

this is my problem...
>> s=tf('s')
s =
s
Continuous-time transfer function.
>> g=1/(1+s)
g =
1
-----
s + 1
Continuous-time transfer function.
>> bode(g) Error using DynamicSystem/bode (line 97) Index exceeds matrix dimensions.
can anyone solve it?

回答(3 个)

Hi,
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.
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);

2 个评论

no, it still doesn't work. i think is a problem of che code or my matlab version... the system says that there is a problem in the line 97 of the code , but I've never touched the source of the code.
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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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.

2 个评论

Hi all,
as stupid it may sound, I have the same problem - bode is not working (any more). Checked possible shadowing, but it seems not the case... Maybe my path is too long (C:\Projects\FHNW\Vorlesungen\HT FHNW\LF Medizinische Automatisierungssysteme\2015FS\03.Unterrichtsvorbereitung\20150316 WK12 - Block 9 - Diskrete Regler\MATLAB')?
Run currently the 8.3.0.532 (R2014a) version, but shall I update to the R2015a? Thx for an answer! BR Lukas
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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