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<h1>gr_iir_filter_ffd.h</h1><a href="gr__iir__filter__ffd_8h.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/* -*- c++ -*- */</span>
<a name="l00002"></a>00002 <span class="comment">/*</span>
<a name="l00003"></a>00003 <span class="comment"> * Copyright 2004 Free Software Foundation, Inc.</span>
<a name="l00004"></a>00004 <span class="comment"> * </span>
<a name="l00005"></a>00005 <span class="comment"> * This file is part of GNU Radio</span>
<a name="l00006"></a>00006 <span class="comment"> * </span>
<a name="l00007"></a>00007 <span class="comment"> * GNU Radio is free software; you can redistribute it and/or modify</span>
<a name="l00008"></a>00008 <span class="comment"> * it under the terms of the GNU General Public License as published by</span>
<a name="l00009"></a>00009 <span class="comment"> * the Free Software Foundation; either version 3, or (at your option)</span>
<a name="l00010"></a>00010 <span class="comment"> * any later version.</span>
<a name="l00011"></a>00011 <span class="comment"> * </span>
<a name="l00012"></a>00012 <span class="comment"> * GNU Radio is distributed in the hope that it will be useful,</span>
<a name="l00013"></a>00013 <span class="comment"> * but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<a name="l00014"></a>00014 <span class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</span>
<a name="l00015"></a>00015 <span class="comment"> * GNU General Public License for more details.</span>
<a name="l00016"></a>00016 <span class="comment"> * </span>
<a name="l00017"></a>00017 <span class="comment"> * You should have received a copy of the GNU General Public License</span>
<a name="l00018"></a>00018 <span class="comment"> * along with GNU Radio; see the file COPYING. If not, write to</span>
<a name="l00019"></a>00019 <span class="comment"> * the Free Software Foundation, Inc., 51 Franklin Street,</span>
<a name="l00020"></a>00020 <span class="comment"> * Boston, MA 02110-1301, USA.</span>
<a name="l00021"></a>00021 <span class="comment"> */</span>
<a name="l00022"></a>00022
<a name="l00023"></a>00023 <span class="preprocessor">#ifndef INCLUDED_GR_IIR_FILTER_FFD_H</span>
<a name="l00024"></a>00024 <span class="preprocessor"></span><span class="preprocessor">#define INCLUDED_GR_IIR_FILTER_FFD_H</span>
<a name="l00025"></a>00025 <span class="preprocessor"></span>
<a name="l00026"></a>00026 <span class="preprocessor">#include <<a class="code" href="gr__sync__block_8h.html">gr_sync_block.h</a>></span>
<a name="l00027"></a>00027 <span class="preprocessor">#include <<a class="code" href="gri__iir_8h.html">gri_iir.h</a>></span>
<a name="l00028"></a>00028 <span class="preprocessor">#include <stdexcept></span>
<a name="l00029"></a>00029
<a name="l00030"></a>00030 <span class="keyword">class </span><a class="code" href="classgr__iir__filter__ffd.html" title="IIR filter with float input, float output and double tapsThis filter uses the Direct...">gr_iir_filter_ffd</a>;
<a name="l00031"></a>00031 <span class="keyword">typedef</span> <a class="code" href="classboost_1_1shared__ptr.html" title="shared_ptr documentation stub">boost::shared_ptr<gr_iir_filter_ffd></a> <a class="code" href="classboost_1_1shared__ptr.html" title="shared_ptr documentation stub">gr_iir_filter_ffd_sptr</a>;
<a name="l00032"></a>00032 <a class="code" href="classboost_1_1shared__ptr.html" title="shared_ptr documentation stub">gr_iir_filter_ffd_sptr</a>
<a name="l00033"></a>00033 <a class="code" href="gr__iir__filter__ffd_8h.html#ac08a7d833832d96349a35afcf4ba8060">gr_make_iir_filter_ffd</a> (<span class="keyword">const</span> <a class="code" href="classstd_1_1vector.html">std::vector<double></a> &fftaps,
<a name="l00034"></a>00034 <span class="keyword">const</span> <a class="code" href="classstd_1_1vector.html">std::vector<double></a> &fbtaps) <span class="keywordflow">throw</span> (std::invalid_argument);
<a name="l00035"></a>00035 <span class="comment"></span>
<a name="l00036"></a>00036 <span class="comment">/*!</span>
<a name="l00037"></a>00037 <span class="comment"> * \brief IIR filter with float input, float output and double taps</span>
<a name="l00038"></a>00038 <span class="comment"> * \ingroup filter_blk</span>
<a name="l00039"></a>00039 <span class="comment"> *</span>
<a name="l00040"></a>00040 <span class="comment"> * This filter uses the Direct Form I implementation, where</span>
<a name="l00041"></a>00041 <span class="comment"> * \p fftaps contains the feed-forward taps, and \p fbtaps the feedback ones.</span>
<a name="l00042"></a>00042 <span class="comment"> *</span>
<a name="l00043"></a>00043 <span class="comment"> * </span>
<a name="l00044"></a>00044 <span class="comment"> * The input and output satisfy a difference equation of the form</span>
<a name="l00045"></a>00045 <span class="comment"></span>
<a name="l00046"></a>00046 <span class="comment"> \f[</span>
<a name="l00047"></a>00047 <span class="comment"> y[n] - \sum_{k=1}^{M} a_k y[n-k] = \sum_{k=0}^{N} b_k x[n-k]</span>
<a name="l00048"></a>00048 <span class="comment"> \f]</span>
<a name="l00049"></a>00049 <span class="comment"></span>
<a name="l00050"></a>00050 <span class="comment"> * with the corresponding rational system function</span>
<a name="l00051"></a>00051 <span class="comment"></span>
<a name="l00052"></a>00052 <span class="comment"> \f[</span>
<a name="l00053"></a>00053 <span class="comment"> H(z) = \frac{\sum_{k=0}^{M} b_k z^{-k}}{1 - \sum_{k=1}^{N} a_k z^{-k}}</span>
<a name="l00054"></a>00054 <span class="comment"> \f]</span>
<a name="l00055"></a>00055 <span class="comment"></span>
<a name="l00056"></a>00056 <span class="comment"> * Note that some texts define the system function with a + in the denominator.</span>
<a name="l00057"></a>00057 <span class="comment"> * If you're using that convention, you'll need to negate the feedback taps.</span>
<a name="l00058"></a>00058 <span class="comment"> */</span>
<a name="l00059"></a><a class="code" href="classgr__iir__filter__ffd.html">00059</a> <span class="keyword">class </span><a class="code" href="classgr__iir__filter__ffd.html" title="IIR filter with float input, float output and double tapsThis filter uses the Direct...">gr_iir_filter_ffd</a> : <span class="keyword">public</span> <a class="code" href="classgr__sync__block.html" title="synchronous 1:1 input to output with historyOverride work to provide the signal processing...">gr_sync_block</a>
<a name="l00060"></a>00060 {
<a name="l00061"></a>00061 <span class="keyword">private</span>:
<a name="l00062"></a>00062 <span class="keyword">friend</span> <a class="code" href="classboost_1_1shared__ptr.html" title="shared_ptr documentation stub">gr_iir_filter_ffd_sptr</a>
<a name="l00063"></a>00063 <a class="code" href="classgr__iir__filter__ffd.html#ac08a7d833832d96349a35afcf4ba8060">gr_make_iir_filter_ffd</a> (<span class="keyword">const</span> <a class="code" href="classstd_1_1vector.html">std::vector<double></a> &fftaps,
<a name="l00064"></a>00064 <span class="keyword">const</span> <a class="code" href="classstd_1_1vector.html">std::vector<double></a> &fbtaps) <span class="keywordflow">throw</span> (std::invalid_argument);
<a name="l00065"></a>00065
<a name="l00066"></a>00066 <a class="code" href="classgri__iir.html">gri_iir<float,float,double></a> d_iir;
<a name="l00067"></a>00067 <a class="code" href="classstd_1_1vector.html">std::vector<double></a> d_new_fftaps;
<a name="l00068"></a>00068 <a class="code" href="classstd_1_1vector.html">std::vector<double></a> d_new_fbtaps;
<a name="l00069"></a>00069 <span class="keywordtype">bool</span> d_updated;
<a name="l00070"></a>00070 <span class="comment"></span>
<a name="l00071"></a>00071 <span class="comment"> /*!</span>
<a name="l00072"></a>00072 <span class="comment"> * Construct an IIR filter with the given taps</span>
<a name="l00073"></a>00073 <span class="comment"> */</span>
<a name="l00074"></a>00074 <a class="code" href="classgr__iir__filter__ffd.html" title="IIR filter with float input, float output and double tapsThis filter uses the Direct...">gr_iir_filter_ffd</a> (<span class="keyword">const</span> <a class="code" href="classstd_1_1vector.html">std::vector<double></a> &fftaps,
<a name="l00075"></a>00075 <span class="keyword">const</span> <a class="code" href="classstd_1_1vector.html">std::vector<double></a> &fbtaps) <span class="keywordflow">throw</span> (std::invalid_argument);
<a name="l00076"></a>00076
<a name="l00077"></a>00077 <span class="keyword">public</span>:
<a name="l00078"></a>00078 <a class="code" href="classgr__iir__filter__ffd.html#ac148a24a79ef56d9bc0bd3c29f8a2c63">~gr_iir_filter_ffd</a> ();
<a name="l00079"></a>00079
<a name="l00080"></a>00080 <span class="keywordtype">void</span> <a class="code" href="classgr__iir__filter__ffd.html#a8b05458a7a2acc934bbec2c51d01ce06">set_taps</a> (<span class="keyword">const</span> <a class="code" href="classstd_1_1vector.html">std::vector<double></a> &fftaps,
<a name="l00081"></a>00081 <span class="keyword">const</span> <a class="code" href="classstd_1_1vector.html">std::vector<double></a> &fbtaps) <span class="keywordflow">throw</span> (std::invalid_argument);
<a name="l00082"></a>00082
<a name="l00083"></a>00083 <span class="keywordtype">int</span> <a class="code" href="classgr__iir__filter__ffd.html#a4770f163efdd77381faebffcac5d4d3f" title="just like gr_block::general_work, only this arranges to call consume_each for you...">work</a> (<span class="keywordtype">int</span> noutput_items,
<a name="l00084"></a>00084 <a class="code" href="classstd_1_1vector.html">gr_vector_const_void_star</a> &input_items,
<a name="l00085"></a>00085 <a class="code" href="classstd_1_1vector.html">gr_vector_void_star</a> &output_items);
<a name="l00086"></a>00086 };
<a name="l00087"></a>00087
<a name="l00088"></a>00088 <span class="preprocessor">#endif</span>
</pre></div></div>
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