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<table border="0" summary="Simple list" class="simplelist_nottable_last">
  <tr>
    <td>
      <a href="constructor_examples_miir.html#empty">Copy a MIIR object</a>
    </td>
  </tr>
  <tr>
    <td>
      <a href="constructor_examples_miir.html#xml_file">Construct a MIIR object by loading the object from a file</a>
    </td>
  </tr>
  <tr>
    <td>
      <a href="constructor_examples_miir.html#parfrac">Construct a MIIR object from a parfrac object <tt>(PARFRAC)</tt></a>
    </td>
  </tr>
  <tr>
    <td>
      <a href="constructor_examples_miir.html#pzmodel">Construct a MIIR object from a pole/zero model <tt>(PZMODEL)</tt></a>
    </td>
  </tr>
  <tr>
    <td>
      <a href="constructor_examples_miir.html#std_type">Construct a MIIR object from a standard type</a>
    </td>
  </tr>
  <tr>
    <td>
      <a href="constructor_examples_miir.html#exist_model">Construct a MIIR object from an existing model</a>
    </td>
  </tr>
  <tr>
    <td>
      <a href="constructor_examples_miir.html#equation">Construct a MIIR object from a difference equation</a>
    </td>
  </tr>
</table>
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<hr>
<h2 class="title"><a name="copy"></a>Copy an IIR filter object</h2>
<p>The following example creates a copy of an IIR filter object (blue command).</p>
<div class="fragment"><pre class="programlisting">
>> iir1 = miir(plist(<span class="string">'type'</span>, <span class="string">'lowpass'</span>));
<span class="blue">>> iir2 = miir(iir2)</span>
------ miir/1 -------
      b: [1 -0.509525449494429]
 histin: 0
version: $Id: miir.m,v 1.98 2009/02/20 15:59:48 nicola Exp
  ntaps: 2
     fs: 1
 infile:
      a: [0.245237275252786 0.245237275252786]
histout: 0
 iunits: [] [1x1 unit]
 ounits: [] [1x1 unit]
   hist: miir.hist  [1x1 history]
   name: lowpass
---------------------
</pre></div>
<br></br>
<p>REMARK: The following command copies only the handle of an object and doesn't create a copy of the object (as above). This means that everything that happens to the copy or original happens to the other object.</p>
<div class="fragment"><pre class="programlisting">
>> iir1 = miir()
------ miir/1 -------
      b: []
 histin: []
version: $Id: miir.m,v 1.98 2009/02/20 15:59:48 nicola Exp
  ntaps: 0
     fs: []
 infile:
      a: []
histout: []
 iunits: [] [1x1 unit]
 ounits: [] [1x1 unit]
   hist: miir.hist  [1x1 history]
   name: none
---------------------
>> iir2 = iir1;
>> iir2.setName(<span class="string">'my new name'</span>)
------ miir/1 -------
      b: []
 histin: []
version: $Id: miir.m,v 1.98 2009/02/20 15:59:48 nicola Exp
  ntaps: 0
     fs: []
 infile:
      a: []
histout: []
 iunits: [] [1x1 unit]
 ounits: [] [1x1 unit]
   hist: miir.hist  [1x1 history]
   name: <span class="string">my new name</span>
---------------------
</pre></div>
<br></br>
<p>If we display iir1 again then we see that the property 'name' was changed although we only have changed iir2.</p>
<div class="fragment"><pre class="programlisting">
>> iir1
------ miir/1 -------
      b: []
 histin: []
version: $Id: miir.m,v 1.98 2009/02/20 15:59:48 nicola Exp
  ntaps: 0
     fs: []
 infile:
      a: []
histout: []
 iunits: [] [1x1 unit]
 ounits: [] [1x1 unit]
   hist: miir.hist  [1x1 history]
   name: <span class="string">my new name</span>
---------------------
</pre></div>


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<hr>
<h2 class="title"><a name="xml_file"></a>Construct a MIIR object by loading the object from a file</h2>
<p>The following example creates a new miir object by loading the miir object from disk.</p>
<div class="fragment"><pre class="programlisting">
f = miir(<span class="string">'f.mat'</span>)
f = miir(<span class="string">'f.xml'</span>)
</pre></div>
<p>or in a <tt>PLIST</tt></p>
<div class="fragment"><pre class="programlisting">
pl  = plist(<span class="string">'filename'</span>, <span class="string">'iir.xml'</span>);
iir = miir(pl)
</pre></div>


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<hr>
<h2 class="title"><a name="parfrac"></a>Construct a MIIR object from a parfrac object</h2>
<p> An IIR filter object can be generated based on a parfrac object. The next example shows how you can convert a parfrac object into a iir filter object.</p>
<div class="fragment"><pre class="programlisting">
pf  = parfrac([1 2+1i 2-1i], [6 1+3i 1-3i], 3);
iir = miir(pf)
</pre></div>
<p>or in a PLIST with the relevant parameters:</p>
<p>
  <table cellspacing="0" border="0" cellpadding="2" class="simplelist_nottable_last" width="80%">
    <colgroup>
      <col width="25%"/>
      <col width="75%"/>
    </colgroup>
    <thead>
      <tr valign="top">
        <th class="subcategorylist">Key</th>
        <th class="subcategorylist">Description</th>
      </tr>
    </thead>
    <tbody>
      <tr valign="top">
        <td>
          <p>'parfrac'</p>
        </td>
        <td>
          <p>a parfrac object to construct the filters from [default: empty parfrac]</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'fs'</p>
        </td>
        <td>
          <p>sample rate for the filter(s) [default: 8 * upper frequency of the parfrac object]</p>
        </td>
      </tr>
    </tbody>
  </table>
</p>
<p>The following example creates a IIR filter object from an parfrac object.</p>
<div class="fragment"><pre class="programlisting">
pf  = parfrac([1 2+1i 2-1i], [6 1+3i 1-3i], 3);
pl  = plist(<span class="string">'parfrac'</span>, pf, <span class="string">'fs'</span>, 100);
</pre></div>


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<hr>
<h2 class="title"><a name="pzmodel"></a>Construct an IIR filter object from a pole/zero model</h2>
<p>The following example creates a new IIR filter object from a pole/zero model.</p>
<div class="fragment"><pre class="programlisting">
>> pzm = pzmodel(1, {1 2 3}, {4 5}, <span class="string">'my pzmodel'</span>)
---- pzmodel 1 ----
    name: my pzmodel
    gain: 1
   delay: 0
  iunits: []
  ounits: []
pole 001: (f=1 Hz,Q=NaN)
pole 002: (f=2 Hz,Q=NaN)
pole 003: (f=3 Hz,Q=NaN)
zero 001: (f=4 Hz,Q=NaN)
zero 002: (f=5 Hz,Q=NaN)
-------------------
>> iir = miir(pzm) <span class="comment">% Use the default sample rate fs=8 * frequency of the highest pole or zero in the model</span>
>> iir = miir(pzm, plist(<span class="string">'fs'</span>, 100))
------ miir/1 -------
      b: [1 -0.6485 -1.9619 1.3364 0.9644 -0.6854]
 histin: [0 0 0 0 0]
version: $Id: miir.m,v 1.98 2009/02/20 15:59:48 nicola Exp
  ntaps: 6
     fs: 100
 infile:
      a: [0.0102 0.0152 -0.0097 -0.0186 0.0019 0.0057]
histout: [0 0 0 0 0]
 iunits: [] [1x1 unit]
 ounits: [] [1x1 unit]
   hist: miir.hist  [1x1 history]
   name: my pzmodel
---------------------
</pre></div>
<p>or in a PLIST with the relevant parameters:</p>
<p>
  <table cellspacing="0" border="0" cellpadding="2" class="simplelist_nottable_last" width="80%">
    <colgroup>
      <col width="25%"/>
      <col width="75%"/>
    </colgroup>
    <thead>
      <tr valign="top">
        <th class="subcategorylist">Key</th>
        <th class="subcategorylist">Description</th>
      </tr>
    </thead>
    <tbody>
      <tr valign="top">
        <td>
          <p>'pzmodel'</p>
        </td>
        <td>
          <p>A pzmodel object to construct the filter from [default: empty pzmodel]</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'fs'</p>
        </td>
        <td>
          <p>Sample rate [default: 8 * frequency of the highest pole or zero in the model]</p>
        </td>
      </tr>
    </tbody>
  </table>
</p>
<div class="fragment"><pre class="programlisting">
>> pzm = pzmodel(1, {1 2 3}, {4 5}, <span class="string">'my pzmodel'</span>)
>> pl  = plist(<span class="string">'pzmodel'</span>, pzm, <span class="string">'fs'</span>, 100)
>> iir = miir(pl)
</pre></div>


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<hr></hr>
<h2 class="title"><a name="std_type"></a>Construct a MIIR object from a standard type</h2>
<p>Construct an IIR filter object from a standard type: 'lowpass', 'highpass', 'bandpass' or 'bandreject'</p>
<p>The relevant parameters are:</p>
<p>
  <table cellspacing="0" border="0" cellpadding="2" class="simplelist_nottable_last" width="80%">
    <colgroup>
      <col width="25%"/>
      <col width="75%"/>
    </colgroup>
    <thead>
      <tr valign="top">
        <th class="subcategorylist">Key</th>
        <th class="subcategorylist">Description</th>
      </tr>
    </thead>
    <tbody>
      <tr valign="top">
        <td>
          <p>'type'</p>
        </td>
        <td>
          <p>one of the types: 'highpass', 'lowpass', 'bandpass', 'bandreject'<br></br>
            [default 'lowpass']</p>
        </td>
      </tr>
    </tbody>
  </table>
</p>
<p>You can also specify optional parameters:</p>
<p>
  <table cellspacing="0" border="0" cellpadding="2" class="simplelist_nottable_last" width="80%">
    <colgroup>
      <col width="25%"/>
      <col width="75%"/>
    </colgroup>
    <thead>
      <tr valign="top">
        <th class="subcategorylist">Key</th>
        <th class="subcategorylist">Description</th>
      </tr>
    </thead>
    <tbody>
      <tr valign="top">
        <td>
          <p>'gain'</p>
        </td>
        <td>
          <p>The gain of the filter [default: 1]</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'fc'</p>
        </td>
        <td>
          <p>The roll-off frequency [default: 0.1 Hz]</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'fs'</p>
        </td>
        <td>
          <p>The sampling frequency to design for [default: 1 Hz]</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'order'</p>
        </td>
        <td>
          <p>The filter order [default: 64]</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'win'</p>
        </td>
        <td>
          <p>Specify window function used in filter design [default: 'Hamming']</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'iunits'</p>
        </td>
        <td>
          <p>the input unit of the filter</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'ounits'</p>
        </td>
        <td>
          <p>the output unit of the filter</p>
        </td>
      </tr>
    </tbody>
  </table>
</p>
<p>The following example creates an order 64 highpass filter with high frequency gain 2. Filter is designed for 1 Hz sampled data and has a cut-off frequency of 0.2 Hz.</p>
<div class="fragment"><pre class="programlisting">
pl = plist(<span class="string">'type'</span>, <span class="string">'highpass'</span>,   ...
                   <span class="string">'order'</span>, 64,  ...
                   <span class="string">'gain'</span>,  2.0, ...
                   <span class="string">'fs'</span>,    1,   ...
                   <span class="string">'fc'</span>,    0.2);
f = miir(pl)
</pre></div>
<p>Furthermore it is possible to specify a spectral window.</p>
<div class="fragment"><pre class="programlisting">
win = specwin(<span class="string">'Kaiser'</span>, 11, 150);
pl = plist(<span class="string">'type'</span>, <span class="string">'lowpass'</span>, ...
           <span class="string">'Win'</span>,   win,      ...
           <span class="string">'fs'</span>,    100,      ...
           <span class="string">'fc'</span>,    20,       ...
           <span class="string">'order'</span>, 10);
f = miir(pl)
</pre></div>


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<hr>
<h2 class="title"><a name="exist_model"></a>Construct a MIIR object from an existing model</h2>
<p>The miir constructor also accepts as an input existing models in different formats:</p>
<p>LISO files</p>
<div class="fragment"><pre class="programlisting">
f = miir(<span class="string">'foo_iir.fil'</span>)
</pre></div>
<p>XML files</p>
<div class="fragment"><pre class="programlisting">
f = miir(<span class="string">'foo_iir.xml'</span>)
</pre></div>
<p>MAT files</p>
<div class="fragment"><pre class="programlisting">
f = miir(<span class="string">'foo_iir.mat'</span>)
</pre></div>
<p>From repository</p>
<p>The relevant parameters for retrieving a IIR filter from a LTPDA repository are:</p>
<p>
  <table cellspacing="0" border="0" cellpadding="2" class="simplelist_nottable_last" width="80%">
    <colgroup>
      <col width="25%"/>
      <col width="75%"/>
    </colgroup>
    <thead>
      <tr valign="top">
        <th class="subcategorylist">Key</th>
        <th class="subcategorylist">Description</th>
      </tr>
    </thead>
    <tbody>
      <tr valign="top">
        <td>
          <p>'hostname'</p>
        </td>
        <td>
          <p>the repository hostname. [default: 'localhost']</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'database'</p>
        </td>
        <td>
          <p>The database name [default: 'ltpda']</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'id'</p>
        </td>
        <td>
          <p>A vector of object IDs. [default: []]</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'cid'</p>
        </td>
        <td>
          <p>Retrieve all rational objects from a particular collection</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'binary'</p>
        </td>
        <td>
          <p>Set to 'yes' to retrieve from stored binary representation (not always available). [default: yes]</p>
        </td>
      </tr>
    </tbody>
  </table>
</p>
<div class="fragment"><pre class="programlisting">
f = miir(plist(<span class="string">'hostname'</span>, <span class="string">'localhost'</span>, <span class="string">'database'</span>, <span class="string">'ltpda'</span>, <span class="string">'ID'</span>, []))
</pre></div>


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<hr>
<h2 class="title"><a name="equation"></a>Construct a MIIR object from a difference equation</h2>
<p>Alternatively, the filter can be defined in terms of two vectors specifying the coefficients of the filter and the sampling frequency. The following example creates a IIR filter with sampling frequency 1 Hz and the following recursive equation:</p>
<div align="center">
  <IMG src="images/sigproc_9.png" width="299" height="28" align="middle" border="0">
</div>
<div class="fragment"><pre class="programlisting">
a  = [0.5 -0.01];
b  = [1 0.1]
fs = 1;

f = miir(a,b,fs)
</pre></div>
<p>or in a <tt>PLIST</tt></p>
<p>The relevant parameters are:</p>
<p>
  <table cellspacing="0" border="0" cellpadding="2" class="simplelist_nottable_last" width="80%">
    <colgroup>
      <col width="25%"/>
      <col width="75%"/>
    </colgroup>
    <thead>
      <tr valign="top">
        <th class="subcategorylist">Key</th>
        <th class="subcategorylist">Description</th>
      </tr>
    </thead>
    <tbody>
      <tr valign="top">
        <td>
          <p>'a'</p>
        </td>
        <td>
          <p>vector of A coefficients (see note ** below) [default: empty]</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'b'</p>
        </td>
        <td>
          <p>vector of B coefficients (see note ** below) [default: empty]</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'fs'</p>
        </td>
        <td>
          <p>sampling frequency of the filter [default: empty]</p>
        </td>
      </tr>
      <tr valign="top">
        <td>
          <p>'name'</p>
        </td>
        <td>
          <p>name of filter [default: 'None']</p>
        </td>
      </tr>
    </tbody>
  </table>
</p>
<div class="fragment"><pre class="programlisting">
a  = [0.5 -0.01];
b  = [1 0.1]
fs = 1;
name = <span class="string">'my IIR'</span>;
pl = plist(<span class="string">'a'</span>, a, <span class="string">'fs'</span>, fs, <span class="string">'name'</span>, name);

iir = miir(pl)
</pre></div>
<br></br>
<div class="fragment">
NOTES:<br></br>
** The convention used here for naming the filter coefficients is the opposite to MATLAB's convention. The recursion formula for this convention is<br></br>
b(1)*y(n) = a(1)*x(n) + a(2)*x(n-1) + ... + a(na+1)*x(n-na) - b(2)*y(n-1) - ... - b(nb+1)*y(n-nb)
</div>

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