<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=9"/>
<meta name="generator" content="Doxygen 1.8.13"/>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<title>aubio: temporal/biquad.h File Reference</title>
<link href="tabs.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="dynsections.js"></script>
<link href="search/search.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="search/searchdata.js"></script>
<script type="text/javascript" src="search/search.js"></script>
<script type="text/x-mathjax-config">
MathJax.Hub.Config({
extensions: ["tex2jax.js"],
jax: ["input/TeX","output/HTML-CSS"],
});
</script><script type="text/javascript" src="http://cdn.mathjax.org/mathjax/latest/MathJax.js"></script>
<link href="doxygen.css" rel="stylesheet" type="text/css" />
</head>
<body>
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
<div id="titlearea">
<table cellspacing="0" cellpadding="0">
<tbody>
<tr style="height: 56px;">
<td id="projectalign" style="padding-left: 0.5em;">
<div id="projectname">aubio
 <span id="projectnumber">0.4.2~alpha</span>
</div>
</td>
</tr>
</tbody>
</table>
</div>
<!-- end header part -->
<!-- Generated by Doxygen 1.8.13 -->
<script type="text/javascript">
var searchBox = new SearchBox("searchBox", "search",false,'Search');
</script>
<script type="text/javascript" src="menudata.js"></script>
<script type="text/javascript" src="menu.js"></script>
<script type="text/javascript">
$(function() {
initMenu('',true,false,'search.php','Search');
$(document).ready(function() { init_search(); });
});
</script>
<div id="main-nav"></div>
<!-- window showing the filter options -->
<div id="MSearchSelectWindow"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
onkeydown="return searchBox.OnSearchSelectKey(event)">
</div>
<!-- iframe showing the search results (closed by default) -->
<div id="MSearchResultsWindow">
<iframe src="javascript:void(0)" frameborder="0"
name="MSearchResults" id="MSearchResults">
</iframe>
</div>
<div id="nav-path" class="navpath">
<ul>
<li class="navelem"><a class="el" href="dir_9f81523443f82c74e7139b3dddc1da52.html">temporal</a></li> </ul>
</div>
</div><!-- top -->
<div class="header">
<div class="summary">
<a href="#func-members">Functions</a> </div>
<div class="headertitle">
<div class="title">biquad.h File Reference</div> </div>
</div><!--header-->
<div class="contents">
<p>Second order Infinite Impulse Response filter.
<a href="#details">More...</a></p>
<p><a href="biquad_8h_source.html">Go to the source code of this file.</a></p>
<table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="func-members"></a>
Functions</h2></td></tr>
<tr class="memitem:a43c7ab92a0c913d4feaed3ede748a603"><td class="memItemLeft" align="right" valign="top"><a class="el" href="types_8h.html#a12a1e9b3ce141648783a82445d02b58d">uint_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="biquad_8h.html#a43c7ab92a0c913d4feaed3ede748a603">aubio_filter_set_biquad</a> (<a class="el" href="filter_8h.html#a49b09d27ea1ef7b06d9948048143f67a">aubio_filter_t</a> *f, <a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> b0, <a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> b1, <a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> b2, <a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> a1, <a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> a2)</td></tr>
<tr class="memdesc:a43c7ab92a0c913d4feaed3ede748a603"><td class="mdescLeft"> </td><td class="mdescRight">set coefficients of a biquad filter <a href="#a43c7ab92a0c913d4feaed3ede748a603">More...</a><br /></td></tr>
<tr class="separator:a43c7ab92a0c913d4feaed3ede748a603"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:aceeb9c15639371381df42664556d7916"><td class="memItemLeft" align="right" valign="top"><a class="el" href="filter_8h.html#a49b09d27ea1ef7b06d9948048143f67a">aubio_filter_t</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="biquad_8h.html#aceeb9c15639371381df42664556d7916">new_aubio_filter_biquad</a> (<a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> b0, <a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> b1, <a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> b2, <a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> a1, <a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> a2)</td></tr>
<tr class="memdesc:aceeb9c15639371381df42664556d7916"><td class="mdescLeft"> </td><td class="mdescRight">create biquad filter with <code>b0</code>, <code>b1</code>, <code>b2</code>, <code>a1</code>, <code>a2</code> coeffs <a href="#aceeb9c15639371381df42664556d7916">More...</a><br /></td></tr>
<tr class="separator:aceeb9c15639371381df42664556d7916"><td class="memSeparator" colspan="2"> </td></tr>
</table>
<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<div class="textblock"><p>Second order Infinite Impulse Response filter. </p>
<p>This file implements a normalised biquad filter (second order IIR):</p>
<p>\( y[n] = b_0 x[n] + b_1 x[n-1] + b_2 x[n-2] - a_1 y[n-1] - a_2 y[n-2] \)</p>
<p>The filtfilt version runs the filter twice, forward and backward, to compensate the phase shifting of the forward operation.</p>
<p>See also <a href="http://en.wikipedia.org/wiki/Digital_biquad_filter">Digital biquad filter</a> on wikipedia. </p>
<p class="definition">Definition in file <a class="el" href="biquad_8h_source.html">biquad.h</a>.</p>
</div><h2 class="groupheader">Function Documentation</h2>
<a id="a43c7ab92a0c913d4feaed3ede748a603"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a43c7ab92a0c913d4feaed3ede748a603">◆ </a></span>aubio_filter_set_biquad()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname"><a class="el" href="types_8h.html#a12a1e9b3ce141648783a82445d02b58d">uint_t</a> aubio_filter_set_biquad </td>
<td>(</td>
<td class="paramtype"><a class="el" href="filter_8h.html#a49b09d27ea1ef7b06d9948048143f67a">aubio_filter_t</a> * </td>
<td class="paramname"><em>f</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> </td>
<td class="paramname"><em>b0</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> </td>
<td class="paramname"><em>b1</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> </td>
<td class="paramname"><em>b2</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> </td>
<td class="paramname"><em>a1</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> </td>
<td class="paramname"><em>a2</em> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td>
</tr>
</table>
</div><div class="memdoc">
<p>set coefficients of a biquad filter </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">f</td><td>filter object as returned by <a class="el" href="filter_8h.html#ae138bb8c05487f09ffbb2c49c79905ca" title="create new filter object ">new_aubio_filter()</a> </td></tr>
<tr><td class="paramname">b0</td><td>forward filter coefficient </td></tr>
<tr><td class="paramname">b1</td><td>forward filter coefficient </td></tr>
<tr><td class="paramname">b2</td><td>forward filter coefficient </td></tr>
<tr><td class="paramname">a1</td><td>feedback filter coefficient </td></tr>
<tr><td class="paramname">a2</td><td>feedback filter coefficient </td></tr>
</table>
</dd>
</dl>
</div>
</div>
<a id="aceeb9c15639371381df42664556d7916"></a>
<h2 class="memtitle"><span class="permalink"><a href="#aceeb9c15639371381df42664556d7916">◆ </a></span>new_aubio_filter_biquad()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname"><a class="el" href="filter_8h.html#a49b09d27ea1ef7b06d9948048143f67a">aubio_filter_t</a>* new_aubio_filter_biquad </td>
<td>(</td>
<td class="paramtype"><a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> </td>
<td class="paramname"><em>b0</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> </td>
<td class="paramname"><em>b1</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> </td>
<td class="paramname"><em>b2</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> </td>
<td class="paramname"><em>a1</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="types_8h.html#a8b426f5dc106056d14afed88c7a17f06">lsmp_t</a> </td>
<td class="paramname"><em>a2</em> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td>
</tr>
</table>
</div><div class="memdoc">
<p>create biquad filter with <code>b0</code>, <code>b1</code>, <code>b2</code>, <code>a1</code>, <code>a2</code> coeffs </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">b0</td><td>forward filter coefficient </td></tr>
<tr><td class="paramname">b1</td><td>forward filter coefficient </td></tr>
<tr><td class="paramname">b2</td><td>forward filter coefficient </td></tr>
<tr><td class="paramname">a1</td><td>feedback filter coefficient </td></tr>
<tr><td class="paramname">a2</td><td>feedback filter coefficient </td></tr>
</table>
</dd>
</dl>
<dl><dt><b>Examples: </b></dt><dd><a class="el" href="temporal_2test-biquad_8c-example.html#a0">temporal/test-biquad.c</a>.</dd>
</dl>
</div>
</div>
</div><!-- contents -->
<!-- start footer part -->
<hr class="footer"/><address class="footer"><small>
Generated by  <a href="http://www.doxygen.org/index.html">
<img class="footer" src="doxygen.png" alt="doxygen"/>
</a> 1.8.13
</small></address>
</body>
</html>
