| <!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"/> |
| <title>CMSIS DSP Software Library: Infinite Impulse Response (IIR) Lattice Filters</title> |
| <link href="tabs.css" rel="stylesheet" type="text/css"/> |
| <link href="search/search.css" rel="stylesheet" type="text/css"/> |
| <script type="text/javaScript" src="search/search.js"></script> |
| <link href="doxygen.css" rel="stylesheet" type="text/css"/> |
| </head> |
| <body onload='searchBox.OnSelectItem(0);'> |
| <!-- Generated by Doxygen 1.7.2 --> |
| <script type="text/javascript"><!-- |
| var searchBox = new SearchBox("searchBox", "search",false,'Search'); |
| --></script> |
| <div class="navigation" id="top"> |
| <div class="tabs"> |
| <ul class="tablist"> |
| <li><a href="index.html"><span>Main Page</span></a></li> |
| <li><a href="modules.html"><span>Modules</span></a></li> |
| <li><a href="annotated.html"><span>Data Structures</span></a></li> |
| <li><a href="files.html"><span>Files</span></a></li> |
| <li><a href="examples.html"><span>Examples</span></a></li> |
| <li id="searchli"> |
| <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> |
| <div class="header"> |
| <div class="summary"> |
| <a href="#func-members">Functions</a> </div> |
| <div class="headertitle"> |
| <h1>Infinite Impulse Response (IIR) Lattice Filters<br/> |
| <small> |
| [<a class="el" href="group__group_filters.html">Filtering Functions</a>]</small> |
| </h1> </div> |
| </div> |
| <div class="contents"> |
| <table class="memberdecls"> |
| <tr><td colspan="2"><h2><a name="func-members"></a> |
| Functions</h2></td></tr> |
| <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group___i_i_r___lattice.html#gaed3b0230bb77439dc902daa625985e04">arm_iir_lattice_init_f32</a> (<a class="el" href="structarm__iir__lattice__instance__f32.html">arm_iir_lattice_instance_f32</a> *S, uint16_t numStages, <a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *pkCoeffs, <a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *pvCoeffs, <a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *pState, uint32_t <a class="el" href="arm__variance__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)</td></tr> |
| <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group___i_i_r___lattice.html#ga56164a0fe48619b8ceec160347bdd2ff">arm_iir_lattice_f32</a> (const <a class="el" href="structarm__iir__lattice__instance__f32.html">arm_iir_lattice_instance_f32</a> *S, <a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *pSrc, <a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *pDst, uint32_t <a class="el" href="arm__variance__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)</td></tr> |
| <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group___i_i_r___lattice.html#gab686c14175581797d9c3ad7bf1d5cc1e">arm_iir_lattice_init_q31</a> (<a class="el" href="structarm__iir__lattice__instance__q31.html">arm_iir_lattice_instance_q31</a> *S, uint16_t numStages, <a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *pkCoeffs, <a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *pvCoeffs, <a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *pState, uint32_t <a class="el" href="arm__variance__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)</td></tr> |
| <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group___i_i_r___lattice.html#ga123b26fa9156cd8d3622dd85931741ed">arm_iir_lattice_q31</a> (const <a class="el" href="structarm__iir__lattice__instance__q31.html">arm_iir_lattice_instance_q31</a> *S, <a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *pSrc, <a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *pDst, uint32_t <a class="el" href="arm__variance__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)</td></tr> |
| <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group___i_i_r___lattice.html#ga1f4bc2dd3d5641e96815d3a5aad58998">arm_iir_lattice_init_q15</a> (<a class="el" href="structarm__iir__lattice__instance__q15.html">arm_iir_lattice_instance_q15</a> *S, uint16_t numStages, <a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *pkCoeffs, <a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *pvCoeffs, <a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *pState, uint32_t <a class="el" href="arm__variance__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)</td></tr> |
| <tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group___i_i_r___lattice.html#gaeb9e9599a288832ed123183eaa8b294a">arm_iir_lattice_q15</a> (const <a class="el" href="structarm__iir__lattice__instance__q15.html">arm_iir_lattice_instance_q15</a> *S, <a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *pSrc, <a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *pDst, uint32_t <a class="el" href="arm__variance__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)</td></tr> |
| </table> |
| <hr/><a name="_details"></a><h2>Detailed Description</h2> |
| <p>This set of functions implements lattice filters for Q15, Q31 and floating-point data types. Lattice filters are used in a variety of adaptive filter applications. The filter structure has feedforward and feedback components and the net impulse response is infinite length. The functions operate on blocks of input and output data and each call to the function processes <code>blockSize</code> samples through the filter. <code>pSrc</code> and <code>pDst</code> point to input and output arrays containing <code>blockSize</code> values.</p> |
| <dl class="user"><dt><b>Algorithm: </b></dt><dd><div align="center"> |
| <img src="IIRLattice.gif" alt="IIRLattice.gif"/> |
| <p><strong>Infinite Impulse Response Lattice filter</strong></p></div> |
| <pre> |
| fN(n) = x(n) |
| fm-1(n) = fm(n) - km * gm-1(n-1) for m = N, N-1, ...1 |
| gm(n) = km * fm-1(n) + gm-1(n-1) for m = N, N-1, ...1 |
| y(n) = vN * gN(n) + vN-1 * gN-1(n) + ...+ v0 * g0(n) |
| </pre> </dd></dl> |
| <dl class="user"><dt><b></b></dt><dd><code>pkCoeffs</code> points to array of reflection coefficients of size <code>numStages</code>. Reflection coefficients are stored in time-reversed order. </dd></dl> |
| <dl class="user"><dt><b></b></dt><dd><pre> |
| {kN, kN-1, ....k1} |
| </pre> <code>pvCoeffs</code> points to the array of ladder coefficients of size <code>(numStages+1)</code>. Ladder coefficients are stored in time-reversed order. </dd></dl> |
| <dl class="user"><dt><b></b></dt><dd><pre> |
| {vN, vN-1, ...v0} |
| </pre> <code>pState</code> points to a state array of size <code>numStages + blockSize</code>. The state variables shown in the figure above (the g values) are stored in the <code>pState</code> array. The state variables are updated after each block of data is processed; the coefficients are untouched. </dd></dl> |
| <dl class="user"><dt><b>Instance Structure </b></dt><dd>The coefficients and state variables for a filter are stored together in an instance data structure. A separate instance structure must be defined for each filter. Coefficient arrays may be shared among several instances while state variable arrays cannot be shared. There are separate instance structure declarations for each of the 3 supported data types.</dd></dl> |
| <dl class="user"><dt><b>Initialization Functions </b></dt><dd>There is also an associated initialization function for each data type. The initialization function performs the following operations:<ul> |
| <li>Sets the values of the internal structure fields.</li> |
| <li>Zeros out the values in the state buffer.</li> |
| </ul> |
| </dd></dl> |
| <dl class="user"><dt><b></b></dt><dd>Use of the initialization function is optional. However, if the initialization function is used, then the instance structure cannot be placed into a const data section. To place an instance structure into a const data section, the instance structure must be manually initialized. Set the values in the state buffer to zeros and then manually initialize the instance structure as follows: <pre> |
| <a class="el" href="structarm__iir__lattice__instance__f32.html" title="Instance structure for the floating-point IIR lattice filter.">arm_iir_lattice_instance_f32</a> S = {numStages, pState, pkCoeffs, pvCoeffs}; |
| <a class="el" href="structarm__iir__lattice__instance__q31.html" title="Instance structure for the Q31 IIR lattice filter.">arm_iir_lattice_instance_q31</a> S = {numStages, pState, pkCoeffs, pvCoeffs}; |
| <a class="el" href="structarm__iir__lattice__instance__q15.html" title="Instance structure for the Q15 IIR lattice filter.">arm_iir_lattice_instance_q15</a> S = {numStages, pState, pkCoeffs, pvCoeffs}; |
| </pre> </dd></dl> |
| <dl class="user"><dt><b></b></dt><dd>where <code>numStages</code> is the number of stages in the filter; <code>pState</code> points to the state buffer array; <code>pkCoeffs</code> points to array of the reflection coefficients; <code>pvCoeffs</code> points to the array of ladder coefficients. </dd></dl> |
| <dl class="user"><dt><b>Fixed-Point Behavior </b></dt><dd>Care must be taken when using the fixed-point versions of the IIR lattice filter functions. In particular, the overflow and saturation behavior of the accumulator used in each function must be considered. Refer to the function specific documentation below for usage guidelines. </dd></dl> |
| <hr/><h2>Function Documentation</h2> |
| <a class="anchor" id="gaed3b0230bb77439dc902daa625985e04"></a><!-- doxytag: member="arm_iir_lattice_init_f32.c::arm_iir_lattice_init_f32" ref="gaed3b0230bb77439dc902daa625985e04" args="(arm_iir_lattice_instance_f32 *S, uint16_t numStages, float32_t *pkCoeffs, float32_t *pvCoeffs, float32_t *pState, uint32_t blockSize)" --> |
| <div class="memitem"> |
| <div class="memproto"> |
| <table class="memname"> |
| <tr> |
| <td class="memname">void arm_iir_lattice_init_f32 </td> |
| <td>(</td> |
| <td class="paramtype"><a class="el" href="structarm__iir__lattice__instance__f32.html">arm_iir_lattice_instance_f32</a> * </td> |
| <td class="paramname"> <em>S</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">uint16_t </td> |
| <td class="paramname"> <em>numStages</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> * </td> |
| <td class="paramname"> <em>pkCoeffs</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> * </td> |
| <td class="paramname"> <em>pvCoeffs</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> * </td> |
| <td class="paramname"> <em>pState</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">uint32_t </td> |
| <td class="paramname"> <em>blockSize</em> </td> |
| </tr> |
| <tr> |
| <td></td> |
| <td>)</td> |
| <td></td><td></td> |
| </tr> |
| </table> |
| </div> |
| <div class="memdoc"> |
| |
| <p>Initialization function for the floating-point IIR lattice filter. </p> |
| <dl><dt><b>Parameters:</b></dt><dd> |
| <table class="params"> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*S</td><td>points to an instance of the floating-point IIR lattice structure. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">numStages</td><td>number of stages in the filter. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pkCoeffs</td><td>points to the reflection coefficient buffer. The array is of length numStages. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pvCoeffs</td><td>points to the ladder coefficient buffer. The array is of length numStages+1. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pState</td><td>points to the state buffer. The array is of length numStages+blockSize. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">blockSize</td><td>number of samples to process. </td></tr> |
| </table> |
| </dd> |
| </dl> |
| <dl class="return"><dt><b>Returns:</b></dt><dd>none. </dd></dl> |
| |
| <p>Definition at line <a class="el" href="arm__iir__lattice__init__f32_8c_source.html#l00055">55</a> of file <a class="el" href="arm__iir__lattice__init__f32_8c_source.html">arm_iir_lattice_init_f32.c</a>.</p> |
| |
| </div> |
| </div> |
| <a class="anchor" id="ga56164a0fe48619b8ceec160347bdd2ff"></a><!-- doxytag: member="arm_iir_lattice_f32.c::arm_iir_lattice_f32" ref="ga56164a0fe48619b8ceec160347bdd2ff" args="(const arm_iir_lattice_instance_f32 *S, float32_t *pSrc, float32_t *pDst, uint32_t blockSize)" --> |
| <div class="memitem"> |
| <div class="memproto"> |
| <table class="memname"> |
| <tr> |
| <td class="memname">void arm_iir_lattice_f32 </td> |
| <td>(</td> |
| <td class="paramtype">const <a class="el" href="structarm__iir__lattice__instance__f32.html">arm_iir_lattice_instance_f32</a> * </td> |
| <td class="paramname"> <em>S</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> * </td> |
| <td class="paramname"> <em>pSrc</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> * </td> |
| <td class="paramname"> <em>pDst</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">uint32_t </td> |
| <td class="paramname"> <em>blockSize</em> </td> |
| </tr> |
| <tr> |
| <td></td> |
| <td>)</td> |
| <td></td><td></td> |
| </tr> |
| </table> |
| </div> |
| <div class="memdoc"> |
| |
| <p>Processing function for the floating-point IIR lattice filter. </p> |
| <dl><dt><b>Parameters:</b></dt><dd> |
| <table class="params"> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*S</td><td>points to an instance of the floating-point IIR lattice structure. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pSrc</td><td>points to the block of input data. </td></tr> |
| <tr><td class="paramdir">[out]</td><td class="paramname">*pDst</td><td>points to the block of output data. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">blockSize</td><td>number of samples to process. </td></tr> |
| </table> |
| </dd> |
| </dl> |
| <dl class="return"><dt><b>Returns:</b></dt><dd>none. </dd></dl> |
| |
| <p>Definition at line <a class="el" href="arm__iir__lattice__f32_8c_source.html#l00120">120</a> of file <a class="el" href="arm__iir__lattice__f32_8c_source.html">arm_iir_lattice_f32.c</a>.</p> |
| |
| </div> |
| </div> |
| <a class="anchor" id="gab686c14175581797d9c3ad7bf1d5cc1e"></a><!-- doxytag: member="arm_iir_lattice_init_q31.c::arm_iir_lattice_init_q31" ref="gab686c14175581797d9c3ad7bf1d5cc1e" args="(arm_iir_lattice_instance_q31 *S, uint16_t numStages, q31_t *pkCoeffs, q31_t *pvCoeffs, q31_t *pState, uint32_t blockSize)" --> |
| <div class="memitem"> |
| <div class="memproto"> |
| <table class="memname"> |
| <tr> |
| <td class="memname">void arm_iir_lattice_init_q31 </td> |
| <td>(</td> |
| <td class="paramtype"><a class="el" href="structarm__iir__lattice__instance__q31.html">arm_iir_lattice_instance_q31</a> * </td> |
| <td class="paramname"> <em>S</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">uint16_t </td> |
| <td class="paramname"> <em>numStages</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> * </td> |
| <td class="paramname"> <em>pkCoeffs</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> * </td> |
| <td class="paramname"> <em>pvCoeffs</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> * </td> |
| <td class="paramname"> <em>pState</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">uint32_t </td> |
| <td class="paramname"> <em>blockSize</em> </td> |
| </tr> |
| <tr> |
| <td></td> |
| <td>)</td> |
| <td></td><td></td> |
| </tr> |
| </table> |
| </div> |
| <div class="memdoc"> |
| |
| <p>Initialization function for the Q31 IIR lattice filter. </p> |
| <dl><dt><b>Parameters:</b></dt><dd> |
| <table class="params"> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*S</td><td>points to an instance of the Q31 IIR lattice structure. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">numStages</td><td>number of stages in the filter. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pkCoeffs</td><td>points to the reflection coefficient buffer. The array is of length numStages. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pvCoeffs</td><td>points to the ladder coefficient buffer. The array is of length numStages+1. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pState</td><td>points to the state buffer. The array is of length numStages+blockSize. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">blockSize</td><td>number of samples to process. </td></tr> |
| </table> |
| </dd> |
| </dl> |
| <dl class="return"><dt><b>Returns:</b></dt><dd>none. </dd></dl> |
| |
| <p>Definition at line <a class="el" href="arm__iir__lattice__init__q31_8c_source.html#l00055">55</a> of file <a class="el" href="arm__iir__lattice__init__q31_8c_source.html">arm_iir_lattice_init_q31.c</a>.</p> |
| |
| </div> |
| </div> |
| <a class="anchor" id="ga123b26fa9156cd8d3622dd85931741ed"></a><!-- doxytag: member="arm_iir_lattice_q31.c::arm_iir_lattice_q31" ref="ga123b26fa9156cd8d3622dd85931741ed" args="(const arm_iir_lattice_instance_q31 *S, q31_t *pSrc, q31_t *pDst, uint32_t blockSize)" --> |
| <div class="memitem"> |
| <div class="memproto"> |
| <table class="memname"> |
| <tr> |
| <td class="memname">void arm_iir_lattice_q31 </td> |
| <td>(</td> |
| <td class="paramtype">const <a class="el" href="structarm__iir__lattice__instance__q31.html">arm_iir_lattice_instance_q31</a> * </td> |
| <td class="paramname"> <em>S</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> * </td> |
| <td class="paramname"> <em>pSrc</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> * </td> |
| <td class="paramname"> <em>pDst</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">uint32_t </td> |
| <td class="paramname"> <em>blockSize</em> </td> |
| </tr> |
| <tr> |
| <td></td> |
| <td>)</td> |
| <td></td><td></td> |
| </tr> |
| </table> |
| </div> |
| <div class="memdoc"> |
| |
| <p>Processing function for the Q31 IIR lattice filter. </p> |
| <dl><dt><b>Parameters:</b></dt><dd> |
| <table class="params"> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*S</td><td>points to an instance of the Q31 IIR lattice structure. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pSrc</td><td>points to the block of input data. </td></tr> |
| <tr><td class="paramdir">[out]</td><td class="paramname">*pDst</td><td>points to the block of output data. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">blockSize</td><td>number of samples to process. </td></tr> |
| </table> |
| </dd> |
| </dl> |
| <dl class="return"><dt><b>Returns:</b></dt><dd>none.</dd></dl> |
| <p><b>Scaling and Overflow Behavior:</b> </p> |
| <dl class="user"><dt><b></b></dt><dd>The function is implemented using an internal 64-bit accumulator. The accumulator has a 2.62 format and maintains full precision of the intermediate multiplication results but provides only a single guard bit. Thus, if the accumulator result overflows it wraps around rather than clip. In order to avoid overflows completely the input signal must be scaled down by 2*log2(numStages) bits. After all multiply-accumulates are performed, the 2.62 accumulator is saturated to 1.32 format and then truncated to 1.31 format. </dd></dl> |
| |
| <p>Definition at line <a class="el" href="arm__iir__lattice__q31_8c_source.html#l00062">62</a> of file <a class="el" href="arm__iir__lattice__q31_8c_source.html">arm_iir_lattice_q31.c</a>.</p> |
| |
| </div> |
| </div> |
| <a class="anchor" id="ga1f4bc2dd3d5641e96815d3a5aad58998"></a><!-- doxytag: member="arm_iir_lattice_init_q15.c::arm_iir_lattice_init_q15" ref="ga1f4bc2dd3d5641e96815d3a5aad58998" args="(arm_iir_lattice_instance_q15 *S, uint16_t numStages, q15_t *pkCoeffs, q15_t *pvCoeffs, q15_t *pState, uint32_t blockSize)" --> |
| <div class="memitem"> |
| <div class="memproto"> |
| <table class="memname"> |
| <tr> |
| <td class="memname">void arm_iir_lattice_init_q15 </td> |
| <td>(</td> |
| <td class="paramtype"><a class="el" href="structarm__iir__lattice__instance__q15.html">arm_iir_lattice_instance_q15</a> * </td> |
| <td class="paramname"> <em>S</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">uint16_t </td> |
| <td class="paramname"> <em>numStages</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> * </td> |
| <td class="paramname"> <em>pkCoeffs</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> * </td> |
| <td class="paramname"> <em>pvCoeffs</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> * </td> |
| <td class="paramname"> <em>pState</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">uint32_t </td> |
| <td class="paramname"> <em>blockSize</em> </td> |
| </tr> |
| <tr> |
| <td></td> |
| <td>)</td> |
| <td></td><td></td> |
| </tr> |
| </table> |
| </div> |
| <div class="memdoc"> |
| |
| <p>Initialization function for the Q15 IIR lattice filter. </p> |
| <dl><dt><b>Parameters:</b></dt><dd> |
| <table class="params"> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*S</td><td>points to an instance of the Q15 IIR lattice structure. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">numStages</td><td>number of stages in the filter. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pkCoeffs</td><td>points to reflection coefficient buffer. The array is of length numStages. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pvCoeffs</td><td>points to ladder coefficient buffer. The array is of length numStages+1. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pState</td><td>points to state buffer. The array is of length numStages+blockSize. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">blockSize</td><td>number of samples to process per call. </td></tr> |
| </table> |
| </dd> |
| </dl> |
| <dl class="return"><dt><b>Returns:</b></dt><dd>none. </dd></dl> |
| |
| <p>Definition at line <a class="el" href="arm__iir__lattice__init__q15_8c_source.html#l00055">55</a> of file <a class="el" href="arm__iir__lattice__init__q15_8c_source.html">arm_iir_lattice_init_q15.c</a>.</p> |
| |
| </div> |
| </div> |
| <a class="anchor" id="gaeb9e9599a288832ed123183eaa8b294a"></a><!-- doxytag: member="arm_iir_lattice_q15.c::arm_iir_lattice_q15" ref="gaeb9e9599a288832ed123183eaa8b294a" args="(const arm_iir_lattice_instance_q15 *S, q15_t *pSrc, q15_t *pDst, uint32_t blockSize)" --> |
| <div class="memitem"> |
| <div class="memproto"> |
| <table class="memname"> |
| <tr> |
| <td class="memname">void arm_iir_lattice_q15 </td> |
| <td>(</td> |
| <td class="paramtype">const <a class="el" href="structarm__iir__lattice__instance__q15.html">arm_iir_lattice_instance_q15</a> * </td> |
| <td class="paramname"> <em>S</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> * </td> |
| <td class="paramname"> <em>pSrc</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> * </td> |
| <td class="paramname"> <em>pDst</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">uint32_t </td> |
| <td class="paramname"> <em>blockSize</em> </td> |
| </tr> |
| <tr> |
| <td></td> |
| <td>)</td> |
| <td></td><td></td> |
| </tr> |
| </table> |
| </div> |
| <div class="memdoc"> |
| |
| <p>Processing function for the Q15 IIR lattice filter. </p> |
| <dl><dt><b>Parameters:</b></dt><dd> |
| <table class="params"> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*S</td><td>points to an instance of the Q15 IIR lattice structure. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">*pSrc</td><td>points to the block of input data. </td></tr> |
| <tr><td class="paramdir">[out]</td><td class="paramname">*pDst</td><td>points to the block of output data. </td></tr> |
| <tr><td class="paramdir">[in]</td><td class="paramname">blockSize</td><td>number of samples to process. </td></tr> |
| </table> |
| </dd> |
| </dl> |
| <dl class="return"><dt><b>Returns:</b></dt><dd>none.</dd></dl> |
| <p><b>Scaling and Overflow Behavior:</b> </p> |
| <dl class="user"><dt><b></b></dt><dd>The function is implemented using a 64-bit internal accumulator. Both coefficients and state variables are represented in 1.15 format and multiplications yield a 2.30 result. The 2.30 intermediate results are accumulated in a 64-bit accumulator in 34.30 format. There is no risk of internal overflow with this approach and the full precision of intermediate multiplications is preserved. After all additions have been performed, the accumulator is truncated to 34.15 format by discarding low 15 bits. Lastly, the accumulator is saturated to yield a result in 1.15 format. </dd></dl> |
| |
| <p>Definition at line <a class="el" href="arm__iir__lattice__q15_8c_source.html#l00063">63</a> of file <a class="el" href="arm__iir__lattice__q15_8c_source.html">arm_iir_lattice_q15.c</a>.</p> |
| |
| </div> |
| </div> |
| </div> |
| <!--- 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"> </span>All</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(1)"><span class="SelectionMark"> </span>Data Structures</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(2)"><span class="SelectionMark"> </span>Files</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(3)"><span class="SelectionMark"> </span>Functions</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(4)"><span class="SelectionMark"> </span>Variables</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(5)"><span class="SelectionMark"> </span>Typedefs</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(6)"><span class="SelectionMark"> </span>Enumerations</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(7)"><span class="SelectionMark"> </span>Enumerator</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(8)"><span class="SelectionMark"> </span>Defines</a></div> |
| |
| <!-- iframe showing the search results (closed by default) --> |
| <div id="MSearchResultsWindow"> |
| <iframe src="" frameborder="0" |
| name="MSearchResults" id="MSearchResults"> |
| </iframe> |
| </div> |
| |
| <hr class="footer"/><address class="footer"><small>Generated on Fri Jul 15 2011 13:16:20 for CMSIS DSP Software Library by  |
| <a href="http://www.doxygen.org/index.html"> |
| <img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.7.2 </small></address> |
| </body> |
| </html> |
