group___r_m_s.html 16 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282
  1. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
  2. <html xmlns="http://www.w3.org/1999/xhtml">
  3. <head>
  4. <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
  5. <meta http-equiv="X-UA-Compatible" content="IE=9"/>
  6. <title>CMSIS-DSP: Root mean square (RMS)</title>
  7. <link href="tabs.css" rel="stylesheet" type="text/css"/>
  8. <link href="cmsis.css" rel="stylesheet" type="text/css" />
  9. <script type="text/javascript" src="jquery.js"></script>
  10. <script type="text/javascript" src="dynsections.js"></script>
  11. <link href="navtree.css" rel="stylesheet" type="text/css"/>
  12. <script type="text/javascript" src="resize.js"></script>
  13. <script type="text/javascript" src="navtree.js"></script>
  14. <script type="text/javascript">
  15. $(document).ready(initResizable);
  16. </script>
  17. <link href="search/search.css" rel="stylesheet" type="text/css"/>
  18. <script type="text/javascript" src="search/search.js"></script>
  19. <script type="text/javascript">
  20. $(document).ready(function() { searchBox.OnSelectItem(0); });
  21. </script>
  22. <link href="stylsheetf" rel="stylesheet" type="text/css" />
  23. </head>
  24. <body>
  25. <div id="top"><!-- do not remove this div, it is closed by doxygen! -->
  26. <div id="titlearea">
  27. <table cellspacing="0" cellpadding="0">
  28. <tbody>
  29. <tr style="height: 46px;">
  30. <td id="projectlogo"><img alt="Logo" src="CMSIS_Logo_Final.png"/></td>
  31. <td style="padding-left: 0.5em;">
  32. <div id="projectname">CMSIS-DSP
  33. &#160;<span id="projectnumber">Version 1.4.4</span>
  34. </div>
  35. <div id="projectbrief">CMSIS DSP Software Library</div>
  36. </td>
  37. </tr>
  38. </tbody>
  39. </table>
  40. </div>
  41. <!-- end header part -->
  42. <div id="CMSISnav" class="tabs1">
  43. <ul class="tablist">
  44. <li><a href="../../General/html/index.html"><span>CMSIS</span></a></li>
  45. <li><a href="../../Core/html/index.html"><span>CORE</span></a></li>
  46. <li><a href="../../Driver/html/index.html"><span>Driver</span></a></li>
  47. <li class="current"><a href="../../DSP/html/index.html"><span>DSP</span></a></li>
  48. <li><a href="../../RTOS/html/index.html"><span>RTOS API</span></a></li>
  49. <li><a href="../../Pack/html/index.html"><span>Pack</span></a></li>
  50. <li><a href="../../SVD/html/index.html"><span>SVD</span></a></li>
  51. </ul>
  52. </div>
  53. <!-- Generated by Doxygen 1.8.2 -->
  54. <script type="text/javascript">
  55. var searchBox = new SearchBox("searchBox", "search",false,'Search');
  56. </script>
  57. <div id="navrow1" class="tabs">
  58. <ul class="tablist">
  59. <li><a href="index.html"><span>Main&#160;Page</span></a></li>
  60. <li><a href="pages.html"><span>Usage&#160;and&#160;Description</span></a></li>
  61. <li><a href="modules.html"><span>Reference</span></a></li>
  62. <li>
  63. <div id="MSearchBox" class="MSearchBoxInactive">
  64. <span class="left">
  65. <img id="MSearchSelect" src="search/mag_sel.png"
  66. onmouseover="return searchBox.OnSearchSelectShow()"
  67. onmouseout="return searchBox.OnSearchSelectHide()"
  68. alt=""/>
  69. <input type="text" id="MSearchField" value="Search" accesskey="S"
  70. onfocus="searchBox.OnSearchFieldFocus(true)"
  71. onblur="searchBox.OnSearchFieldFocus(false)"
  72. onkeyup="searchBox.OnSearchFieldChange(event)"/>
  73. </span><span class="right">
  74. <a id="MSearchClose" href="javascript:searchBox.CloseResultsWindow()"><img id="MSearchCloseImg" border="0" src="search/close.png" alt=""/></a>
  75. </span>
  76. </div>
  77. </li>
  78. </ul>
  79. </div>
  80. </div><!-- top -->
  81. <div id="side-nav" class="ui-resizable side-nav-resizable">
  82. <div id="nav-tree">
  83. <div id="nav-tree-contents">
  84. <div id="nav-sync" class="sync"></div>
  85. </div>
  86. </div>
  87. <div id="splitbar" style="-moz-user-select:none;"
  88. class="ui-resizable-handle">
  89. </div>
  90. </div>
  91. <script type="text/javascript">
  92. $(document).ready(function(){initNavTree('group___r_m_s.html','');});
  93. </script>
  94. <div id="doc-content">
  95. <!-- window showing the filter options -->
  96. <div id="MSearchSelectWindow"
  97. onmouseover="return searchBox.OnSearchSelectShow()"
  98. onmouseout="return searchBox.OnSearchSelectHide()"
  99. onkeydown="return searchBox.OnSearchSelectKey(event)">
  100. <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>
  101. <!-- iframe showing the search results (closed by default) -->
  102. <div id="MSearchResultsWindow">
  103. <iframe src="javascript:void(0)" frameborder="0"
  104. name="MSearchResults" id="MSearchResults">
  105. </iframe>
  106. </div>
  107. <div class="header">
  108. <div class="summary">
  109. <a href="#func-members">Functions</a> </div>
  110. <div class="headertitle">
  111. <div class="title">Root mean square (RMS)</div> </div>
  112. <div class="ingroups"><a class="el" href="group__group_stats.html">Statistics Functions</a></div></div><!--header-->
  113. <div class="contents">
  114. <table class="memberdecls">
  115. <tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="func-members"></a>
  116. Functions</h2></td></tr>
  117. <tr class="memitem:ga0e3ab1b57da32d45388d1fa90d7fd88c"><td class="memItemLeft" align="right" valign="top">void&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group___r_m_s.html#ga0e3ab1b57da32d45388d1fa90d7fd88c">arm_rms_f32</a> (<a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *pSrc, uint32_t <a class="el" href="arm__variance__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>, <a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *pResult)</td></tr>
  118. <tr class="memdesc:ga0e3ab1b57da32d45388d1fa90d7fd88c"><td class="mdescLeft">&#160;</td><td class="mdescRight">Root Mean Square of the elements of a floating-point vector. <a href="#ga0e3ab1b57da32d45388d1fa90d7fd88c"></a><br/></td></tr>
  119. <tr class="separator:ga0e3ab1b57da32d45388d1fa90d7fd88c"><td class="memSeparator" colspan="2">&#160;</td></tr>
  120. <tr class="memitem:gaf5b836b72dda9e5dfbbd17c7906fd13f"><td class="memItemLeft" align="right" valign="top">void&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group___r_m_s.html#gaf5b836b72dda9e5dfbbd17c7906fd13f">arm_rms_q15</a> (<a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *pSrc, uint32_t <a class="el" href="arm__variance__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>, <a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *pResult)</td></tr>
  121. <tr class="memdesc:gaf5b836b72dda9e5dfbbd17c7906fd13f"><td class="mdescLeft">&#160;</td><td class="mdescRight">Root Mean Square of the elements of a Q15 vector. <a href="#gaf5b836b72dda9e5dfbbd17c7906fd13f"></a><br/></td></tr>
  122. <tr class="separator:gaf5b836b72dda9e5dfbbd17c7906fd13f"><td class="memSeparator" colspan="2">&#160;</td></tr>
  123. <tr class="memitem:gae33015fda23fc44e7ead5e5ed7e8d314"><td class="memItemLeft" align="right" valign="top">void&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group___r_m_s.html#gae33015fda23fc44e7ead5e5ed7e8d314">arm_rms_q31</a> (<a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *pSrc, uint32_t <a class="el" href="arm__variance__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>, <a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *pResult)</td></tr>
  124. <tr class="memdesc:gae33015fda23fc44e7ead5e5ed7e8d314"><td class="mdescLeft">&#160;</td><td class="mdescRight">Root Mean Square of the elements of a Q31 vector. <a href="#gae33015fda23fc44e7ead5e5ed7e8d314"></a><br/></td></tr>
  125. <tr class="separator:gae33015fda23fc44e7ead5e5ed7e8d314"><td class="memSeparator" colspan="2">&#160;</td></tr>
  126. </table>
  127. <a name="details" id="details"></a><h2 class="groupheader">Description</h2>
  128. <p>Calculates the Root Mean Sqaure of the elements in the input vector. The underlying algorithm is used:</p>
  129. <pre>
  130. Result = sqrt(((pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + ... + pSrc[blockSize-1] * pSrc[blockSize-1]) / blockSize));
  131. </pre><p>There are separate functions for floating point, Q31, and Q15 data types. </p>
  132. <h2 class="groupheader">Function Documentation</h2>
  133. <a class="anchor" id="ga0e3ab1b57da32d45388d1fa90d7fd88c"></a>
  134. <div class="memitem">
  135. <div class="memproto">
  136. <table class="memname">
  137. <tr>
  138. <td class="memname">void arm_rms_f32 </td>
  139. <td>(</td>
  140. <td class="paramtype"><a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *&#160;</td>
  141. <td class="paramname"><em>pSrc</em>, </td>
  142. </tr>
  143. <tr>
  144. <td class="paramkey"></td>
  145. <td></td>
  146. <td class="paramtype">uint32_t&#160;</td>
  147. <td class="paramname"><em>blockSize</em>, </td>
  148. </tr>
  149. <tr>
  150. <td class="paramkey"></td>
  151. <td></td>
  152. <td class="paramtype"><a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *&#160;</td>
  153. <td class="paramname"><em>pResult</em>&#160;</td>
  154. </tr>
  155. <tr>
  156. <td></td>
  157. <td>)</td>
  158. <td></td><td></td>
  159. </tr>
  160. </table>
  161. </div><div class="memdoc">
  162. <dl class="params"><dt>Parameters</dt><dd>
  163. <table class="params">
  164. <tr><td class="paramdir">[in]</td><td class="paramname">*pSrc</td><td>points to the input vector </td></tr>
  165. <tr><td class="paramdir">[in]</td><td class="paramname">blockSize</td><td>length of the input vector </td></tr>
  166. <tr><td class="paramdir">[out]</td><td class="paramname">*pResult</td><td>rms value returned here </td></tr>
  167. </table>
  168. </dd>
  169. </dl>
  170. <dl class="section return"><dt>Returns</dt><dd>none. </dd></dl>
  171. <p>References <a class="el" href="group___s_q_r_t.html#ga56a40d1cf842b0b45267df6761975da0">arm_sqrt_f32()</a>, and <a class="el" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>.</p>
  172. </div>
  173. </div>
  174. <a class="anchor" id="gaf5b836b72dda9e5dfbbd17c7906fd13f"></a>
  175. <div class="memitem">
  176. <div class="memproto">
  177. <table class="memname">
  178. <tr>
  179. <td class="memname">void arm_rms_q15 </td>
  180. <td>(</td>
  181. <td class="paramtype"><a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *&#160;</td>
  182. <td class="paramname"><em>pSrc</em>, </td>
  183. </tr>
  184. <tr>
  185. <td class="paramkey"></td>
  186. <td></td>
  187. <td class="paramtype">uint32_t&#160;</td>
  188. <td class="paramname"><em>blockSize</em>, </td>
  189. </tr>
  190. <tr>
  191. <td class="paramkey"></td>
  192. <td></td>
  193. <td class="paramtype"><a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *&#160;</td>
  194. <td class="paramname"><em>pResult</em>&#160;</td>
  195. </tr>
  196. <tr>
  197. <td></td>
  198. <td>)</td>
  199. <td></td><td></td>
  200. </tr>
  201. </table>
  202. </div><div class="memdoc">
  203. <dl class="params"><dt>Parameters</dt><dd>
  204. <table class="params">
  205. <tr><td class="paramdir">[in]</td><td class="paramname">*pSrc</td><td>points to the input vector </td></tr>
  206. <tr><td class="paramdir">[in]</td><td class="paramname">blockSize</td><td>length of the input vector </td></tr>
  207. <tr><td class="paramdir">[out]</td><td class="paramname">*pResult</td><td>rms value returned here </td></tr>
  208. </table>
  209. </dd>
  210. </dl>
  211. <dl class="section return"><dt>Returns</dt><dd>none.</dd></dl>
  212. <p><b>Scaling and Overflow Behavior:</b></p>
  213. <dl class="section user"><dt></dt><dd>The function is implemented using a 64-bit internal accumulator. The input is represented in 1.15 format. Intermediate multiplication yields a 2.30 format, and this result is added without saturation to a 64-bit accumulator in 34.30 format. With 33 guard bits in the accumulator, there is no risk of overflow, and the full precision of the intermediate multiplication is preserved. Finally, the 34.30 result is truncated to 34.15 format by discarding the lower 15 bits, and then saturated to yield a result in 1.15 format. </dd></dl>
  214. <p>References <a class="el" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248">__SIMD32</a>, <a class="el" href="group___s_q_r_t.html#ga5abe5ca724f3e15849662b03752c1238">arm_sqrt_q15()</a>, and <a class="el" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>.</p>
  215. </div>
  216. </div>
  217. <a class="anchor" id="gae33015fda23fc44e7ead5e5ed7e8d314"></a>
  218. <div class="memitem">
  219. <div class="memproto">
  220. <table class="memname">
  221. <tr>
  222. <td class="memname">void arm_rms_q31 </td>
  223. <td>(</td>
  224. <td class="paramtype"><a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *&#160;</td>
  225. <td class="paramname"><em>pSrc</em>, </td>
  226. </tr>
  227. <tr>
  228. <td class="paramkey"></td>
  229. <td></td>
  230. <td class="paramtype">uint32_t&#160;</td>
  231. <td class="paramname"><em>blockSize</em>, </td>
  232. </tr>
  233. <tr>
  234. <td class="paramkey"></td>
  235. <td></td>
  236. <td class="paramtype"><a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *&#160;</td>
  237. <td class="paramname"><em>pResult</em>&#160;</td>
  238. </tr>
  239. <tr>
  240. <td></td>
  241. <td>)</td>
  242. <td></td><td></td>
  243. </tr>
  244. </table>
  245. </div><div class="memdoc">
  246. <dl class="params"><dt>Parameters</dt><dd>
  247. <table class="params">
  248. <tr><td class="paramdir">[in]</td><td class="paramname">*pSrc</td><td>points to the input vector </td></tr>
  249. <tr><td class="paramdir">[in]</td><td class="paramname">blockSize</td><td>length of the input vector </td></tr>
  250. <tr><td class="paramdir">[out]</td><td class="paramname">*pResult</td><td>rms value returned here </td></tr>
  251. </table>
  252. </dd>
  253. </dl>
  254. <dl class="section return"><dt>Returns</dt><dd>none.</dd></dl>
  255. <p><b>Scaling and Overflow Behavior:</b></p>
  256. <dl class="section user"><dt></dt><dd>The function is implemented using an internal 64-bit accumulator. The input is represented in 1.31 format, and intermediate multiplication yields a 2.62 format. The accumulator maintains full precision of the intermediate multiplication results, but provides only a single guard bit. There is no saturation on intermediate additions. If the accumulator overflows, it wraps around and distorts the result. In order to avoid overflows completely, the input signal must be scaled down by log2(blockSize) bits, as a total of blockSize additions are performed internally. Finally, the 2.62 accumulator is right shifted by 31 bits to yield a 1.31 format value. </dd></dl>
  257. <p>References <a class="el" href="group___s_q_r_t.html#ga119e25831e141d734d7ef10636670058">arm_sqrt_q31()</a>, <a class="el" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>, and <a class="el" href="arm__math_8h.html#ad7373e53d3c2e1adfeafc8c2e9720b5c">clip_q63_to_q31()</a>.</p>
  258. </div>
  259. </div>
  260. </div><!-- contents -->
  261. </div><!-- doc-content -->
  262. <!-- start footer part -->
  263. <div id="nav-path" class="navpath"><!-- id is needed for treeview function! -->
  264. <ul>
  265. <li class="footer">Generated on Tue Sep 23 2014 18:52:43 for CMSIS-DSP by ARM Ltd. All rights reserved.
  266. <!--
  267. <a href="http://www.doxygen.org/index.html">
  268. <img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.8.2
  269. -->
  270. </li>
  271. </ul>
  272. </div>
  273. </body>
  274. </html>