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  <title>Converting models between different representations (LTPDA Toolbox)</title>
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  <h1 class="title"><a name="f3-12899" id="f3-12899"></a>Converting models between different representations</h1>
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  <p>
	The different constructors from each transfer function representations accept as
an input a model from a another representation so that they can all be converted
between the different representations. In the current LTPDA version, this applies
for pole/zero model and rational representation. Following versions will cover the
partial fraction representation. This is shown in the following transformation table:

<div align="center">
  <img src="images/TransformTable.png" alt="Pole/zero model TF" border="3">
</div>

<h2>From pzmodel to rational</a></h2>
You can transform a <tt>pzmodel</tt> into a <tt>rational</tt> by typing:
<br>
<div class="fragment"><pre>
    >> rat   = rational(pzmodel)
</pre></div>
<br>

<h2>From rational to pzmodel</a></h2>
You can transform a <tt>rational</tt> into a <tt>pzmodel</tt> by typing:
<br>
<div class="fragment"><pre>
    >> rat   = pzmodel(rational)
</pre></div>
<br>

<h2>Algorithm</a></h2>
To translate from <tt>rational</tt> to <tt>pzmodel</tt> representation we need to
compute the roots of a polynomial and the inverse operation is performed going from
<tt>pzmodel</tt> to <tt>rational</tt>. More information about the algorithm used can be
found in MATLAB's functions <a href="matlab:doc('poly')">poly</a> and
<a href="matlab:doc('roots')">roots</a>.


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author	Daniele Nicolodi <nicolodi@science.unitn.it>
date	Wed, 07 Dec 2011 17:24:37 +0100
parents	f0afece42f48
children