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## Re: SIMO systems

 From: Geraint Paul Bevan Subject: Re: SIMO systems Date: Thu, 31 Jul 2003 07:50:23 +0100 User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624

```Mauro Casse wrote:
```
Hi, I can't find how to do this, I must obtain the space state representation of the followig transfer function with single input and two outputs
```                    1                [  1  ]
G(s) = ------------------- * |       | (this is a column vector)
s^2+5*s+1       [ s+1]

the following commands works in Matlab, but octave return this error

octave:26> num = [ 0 1; 1 1];
octave:27> den = [ 1 5 6 ];
octave:28> [ A, B, C, D] = tf2ss(num,den)
error: num(2x2) must be a vector
error: evaluating if command near line 51, column 3
error: called from /usr/local/share/octave/2.1.50/m/control/sys

```
```

```
tf2ss requires the numerator to have only one column, i.e. it only works with simple gains in the numerator. You can create the state space representation manually however:
```

octave> [A,B,C1,D1] = tf2ss (    1  , [1,5,6] );
octave> [A,B,C2,D2] = tf2ss ( [1,1] , [1,5,6] );
octave> C = [C1;C2];
octave> D = [D1;D2];
octave> A,B,C,D
A =

0   1
-6  -5

B =

0
1

C =

1  0
1  1

D =

0
0

--
Geraint Bevan
Department of Mechanical Engineering
University of Glasgow
Tel: +44 (0)141 330 5917

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```