GNU Radio 3.6.0 C++ API
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00001 /* -*- c++ -*- */ 00002 /* 00003 * Copyright 2004,2005,2006 Free Software Foundation, Inc. 00004 * 00005 * This file is part of GNU Radio 00006 * 00007 * GNU Radio is free software; you can redistribute it and/or modify 00008 * it under the terms of the GNU General Public License as published by 00009 * the Free Software Foundation; either version 3, or (at your option) 00010 * any later version. 00011 * 00012 * GNU Radio is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00015 * GNU General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU General Public License 00018 * along with GNU Radio; see the file COPYING. If not, write to 00019 * the Free Software Foundation, Inc., 51 Franklin Street, 00020 * Boston, MA 02110-1301, USA. 00021 */ 00022 00023 #ifndef INCLUDED_GR_SINGLE_POLE_IIR_FILTER_CC_H 00024 #define INCLUDED_GR_SINGLE_POLE_IIR_FILTER_CC_H 00025 00026 #include <gr_core_api.h> 00027 #include <gr_sync_block.h> 00028 #include <gr_single_pole_iir.h> 00029 #include <gr_complex.h> 00030 #include <stdexcept> 00031 00032 class gr_single_pole_iir_filter_cc; 00033 typedef boost::shared_ptr<gr_single_pole_iir_filter_cc> gr_single_pole_iir_filter_cc_sptr; 00034 00035 GR_CORE_API gr_single_pole_iir_filter_cc_sptr 00036 gr_make_single_pole_iir_filter_cc (double alpha, unsigned int vlen=1); 00037 00038 /*! 00039 * \brief single pole IIR filter with complex input, complex output 00040 * \ingroup filter_blk 00041 * 00042 * The input and output satisfy a difference equation of the form 00043 \htmlonly 00044 \f{ 00045 y[n] - (1-alpha) y[n-1] = alpha x[n] 00046 \f} 00047 \endhtmlonly 00048 00049 \xmlonly 00050 y[n] - (1-alpha) y[n-1] = alpha x[n] 00051 \endxmlonly 00052 00053 * with the corresponding rational system function 00054 \htmlonly 00055 \f{ 00056 H(z) = \frac{alpha}{1 - (1-alpha) z^{-1}} 00057 \f} 00058 \endhtmlonly 00059 00060 \xmlonly 00061 H(z) = \ frac{alpha}{1 - (1-alpha) z^{-1}} 00062 \endxmlonly 00063 00064 * Note that some texts define the system function with a + in the denominator. 00065 * If you're using that convention, you'll need to negate the feedback tap. 00066 */ 00067 class GR_CORE_API gr_single_pole_iir_filter_cc : public gr_sync_block 00068 { 00069 private: 00070 friend GR_CORE_API gr_single_pole_iir_filter_cc_sptr 00071 gr_make_single_pole_iir_filter_cc (double alpha, unsigned int vlen); 00072 00073 unsigned int d_vlen; 00074 std::vector<gr_single_pole_iir<gr_complex,gr_complex,double> > d_iir; 00075 00076 gr_single_pole_iir_filter_cc (double alpha, unsigned int vlen); 00077 00078 public: 00079 ~gr_single_pole_iir_filter_cc (); 00080 00081 void set_taps (double alpha); 00082 00083 int work (int noutput_items, 00084 gr_vector_const_void_star &input_items, 00085 gr_vector_void_star &output_items); 00086 }; 00087 00088 #endif