<p>
  Transfer functions can be expressed as a quocient of polynomials
</p>
<br>
<div align="center">
  <img src="images/parfrac_tf_eqn.png" alt="Pole/zero model TF" border="3">
</div>
<br>
<p>
  The constructor can be used in different ways
</p>
<h2>From poles and residues</a></h2>
<p>
  The standard way is to input the coefficients of your filter. The constructor
  accepts as a optional properties the name
</p>
<br>
<div class="fragment"><pre>
    >> par = parfrac([1 2+1i 2-1i], [6 1+3i 1-3i], [])
    ---- parfrac 1 ----
    model:    None
    res:      [1;2+i*1;2-i*1]
    poles:    [6;1+i*3;1-i*3]
    dir:      0
    pmul:     [1;1;1]
    iunits:   []
    ounits:   []
    -------------------
</pre></div>
<br>
<h2>From partial XML file</a></h2>
You can input a XML file containing a transfer function model into the constructor
<br>
<div class="fragment"><pre>
    >> par   = parfrac('datafile.xml')
</pre></div>
<br>
<h2>From mat file</a></h2>
You can input a mat file containing a transfer function model into the constructor
<br>
<div class="fragment"><pre>
    >> rat   = parfrac('datafile.mat')
</pre></div>
<br>
<h2>From plist</a></h2>
All the properties of the filter can be specified in a plist and then passed to the constructor:
<br>
<div class="fragment"><pre>
    >> pl = plist('iunits','m','ounits','V','res',[1 2+1i 2-1i],'poles',[6 1+3i 1-3i],...
    'name','filter_mame');
    >> par = parfrac(pl)
    ---- parfrac 1 ----
    model:    filter_mame
    res:      [1;2+i*1;2-i*1]
    poles:    [6;1+i*3;1-i*3]
    dir:      0
    pmul:     [1;1;1]
    iunits:   [m]
    ounits:   [V]
    -------------------
</pre></div>
<br>
<h2>From repository</a></h2>
Rational transfer function can be obtained from the <a href="repo.html"> repository </a> with the following syntax.
<br>
<div class="fragment"><pre>
    >> rat   = rational('Hostname','localhost','Database','ltpda',...
    'ID',[],'CID',[],'Binary',yes)
</pre></div>
<br>