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>.