xmclib/CMSIS/Documentation/DSP/html/group__VarianceExample.html

158 lines
8.7 KiB
HTML
Raw Permalink Normal View History

2024-10-17 17:09:59 +02:00
<!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"/>
<title>Variance Example</title>
<title>CMSIS-DSP: Variance Example</title>
<link href="tabs.css" rel="stylesheet" type="text/css"/>
<link href="cmsis.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="dynsections.js"></script>
<script type="text/javascript" src="printComponentTabs.js"></script>
<link href="navtree.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="resize.js"></script>
<script type="text/javascript" src="navtree.js"></script>
<script type="text/javascript">
$(document).ready(initResizable);
$(window).load(resizeHeight);
</script>
<link href="search/search.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="search/search.js"></script>
<script type="text/javascript">
$(document).ready(function() { searchBox.OnSelectItem(0); });
</script>
</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: 46px;">
<td id="projectlogo"><img alt="Logo" src="CMSIS_Logo_Final.png"/></td>
<td style="padding-left: 0.5em;">
<div id="projectname">CMSIS-DSP
&#160;<span id="projectnumber">Version 1.5.1</span>
</div>
<div id="projectbrief">CMSIS DSP Software Library</div>
</td>
</tr>
</tbody>
</table>
</div>
<!-- end header part -->
<div id="CMSISnav" class="tabs1">
<ul class="tablist">
<script type="text/javascript">
<!--
writeComponentTabs.call(this);
//-->
</script>
</ul>
</div>
<!-- Generated by Doxygen 1.8.6 -->
<script type="text/javascript">
var searchBox = new SearchBox("searchBox", "search",false,'Search');
</script>
<div id="navrow1" class="tabs">
<ul class="tablist">
<li><a href="index.html"><span>Main&#160;Page</span></a></li>
<li><a href="pages.html"><span>Usage&#160;and&#160;Description</span></a></li>
<li><a href="modules.html"><span>Reference</span></a></li>
<li>
<div id="MSearchBox" class="MSearchBoxInactive">
<span class="left">
<img id="MSearchSelect" src="search/mag_sel.png"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
alt=""/>
<input type="text" id="MSearchField" value="Search" accesskey="S"
onfocus="searchBox.OnSearchFieldFocus(true)"
onblur="searchBox.OnSearchFieldFocus(false)"
onkeyup="searchBox.OnSearchFieldChange(event)"/>
</span><span class="right">
<a id="MSearchClose" href="javascript:searchBox.CloseResultsWindow()"><img id="MSearchCloseImg" border="0" src="search/close.png" alt=""/></a>
</span>
</div>
</li>
</ul>
</div>
</div><!-- top -->
<div id="side-nav" class="ui-resizable side-nav-resizable">
<div id="nav-tree">
<div id="nav-tree-contents">
<div id="nav-sync" class="sync"></div>
</div>
</div>
<div id="splitbar" style="-moz-user-select:none;"
class="ui-resizable-handle">
</div>
</div>
<script type="text/javascript">
$(document).ready(function(){initNavTree('group__VarianceExample.html','');});
</script>
<div id="doc-content">
<!-- window showing the filter options -->
<div id="MSearchSelectWindow"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
onkeydown="return searchBox.OnSearchSelectKey(event)">
<a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(0)"><span class="SelectionMark">&#160;</span>All</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(1)"><span class="SelectionMark">&#160;</span>Data Structures</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(2)"><span class="SelectionMark">&#160;</span>Files</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(3)"><span class="SelectionMark">&#160;</span>Functions</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(4)"><span class="SelectionMark">&#160;</span>Variables</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(5)"><span class="SelectionMark">&#160;</span>Typedefs</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(6)"><span class="SelectionMark">&#160;</span>Enumerations</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(7)"><span class="SelectionMark">&#160;</span>Enumerator</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(8)"><span class="SelectionMark">&#160;</span>Macros</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(9)"><span class="SelectionMark">&#160;</span>Groups</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(10)"><span class="SelectionMark">&#160;</span>Pages</a></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 class="header">
<div class="headertitle">
<div class="title">Variance Example<div class="ingroups"><a class="el" href="group__groupExamples.html">Examples</a></div></div> </div>
</div><!--header-->
<div class="contents">
<dl class="section user"><dt>Description:</dt><dd></dd></dl>
<dl class="section user"><dt></dt><dd>Demonstrates the use of Basic Math and Support Functions to calculate the variance of an input sequence with N samples. Uniformly distributed white noise is taken as input.</dd></dl>
<dl class="section user"><dt>Algorithm:</dt><dd></dd></dl>
<dl class="section user"><dt></dt><dd>The variance of a sequence is the mean of the squared deviation of the sequence from its mean. </dd></dl>
<dl class="section user"><dt></dt><dd>This is denoted by the following equation: <pre> variance = ((x[0] - x') * (x[0] - x') + (x[1] - x') * (x[1] - x') + ... + * (x[n-1] - x') * (x[n-1] - x')) / (N-1)</pre> where, <code>x[n]</code> is the input sequence, <code>N</code> is the number of input samples, and <code>x'</code> is the mean value of the input sequence, <code>x[n]</code>. </dd></dl>
<dl class="section user"><dt></dt><dd>The mean value <code>x'</code> is defined as: <pre> x' = (x[0] + x[1] + ... + x[n-1]) / N</pre></dd></dl>
<dl class="section user"><dt>Block Diagram:</dt><dd></dd></dl>
<dl class="section user"><dt></dt><dd><div class="image">
<img src="Variance.gif" alt="Variance.gif"/>
</div>
</dd></dl>
<dl class="section user"><dt>Variables Description:</dt><dd></dd></dl>
<dl class="section user"><dt></dt><dd><ul>
<li><code>testInput_f32</code> points to the input data </li>
<li><code>wire1</code>, <code>wir2</code>, <code>wire3</code> temporary buffers </li>
<li><code>blockSize</code> number of samples processed at a time </li>
<li><code>refVarianceOut</code> reference variance value</li>
</ul>
</dd></dl>
<dl class="section user"><dt>CMSIS DSP Software Library Functions Used:</dt><dd></dd></dl>
<dl class="section user"><dt></dt><dd><ul>
<li><a class="el" href="group__dot__prod.html#ga55418d4362f6ba84c327f9b4f089a8c3" title="Dot product of floating-point vectors. ">arm_dot_prod_f32()</a></li>
<li><a class="el" href="group__BasicMult.html#gaca3f0b8227da431ab29225b88888aa32" title="Floating-point vector multiplication. ">arm_mult_f32()</a></li>
<li><a class="el" href="group__BasicSub.html#ga7f975a472de286331134227c08aad826" title="Floating-point vector subtraction. ">arm_sub_f32()</a></li>
<li><a class="el" href="group__Fill.html#ga2248e8d3901b4afb7827163132baad94" title="Fills a constant value into a floating-point vector. ">arm_fill_f32()</a></li>
<li><a class="el" href="group__copy.html#gadd1f737e677e0e6ca31767c7001417b3" title="Copies the elements of a floating-point vector. ">arm_copy_f32()</a></li>
</ul>
</dd></dl>
<p><b> Refer </b> <a class="el" href="arm_variance_example_f32_8c-example.html">arm_variance_example_f32.c</a> </p>
</div><!-- contents -->
</div><!-- doc-content -->
<!-- start footer part -->
<div id="nav-path" class="navpath"><!-- id is needed for treeview function! -->
<ul>
<li class="footer">Generated on Wed Feb 8 2017 10:20:51 for CMSIS-DSP by ARM Ltd. All rights reserved.
<!--
<a href="http://www.doxygen.org/index.html">
<img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.8.6
-->
</li>
</ul>
</div>
</body>
</html>