GNU Radio 3.7.0 C++ API
|
00001 /* -*- c++ -*- */ 00002 /* 00003 * Copyright 2004,2005 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_SINGLE_POLE_IIR_FILTER_FF_H 00024 #define INCLUDED_SINGLE_POLE_IIR_FILTER_FF_H 00025 00026 #include <gnuradio/filter/api.h> 00027 #include <gnuradio/filter/single_pole_iir.h> 00028 #include <gnuradio/sync_block.h> 00029 #include <gnuradio/gr_complex.h> 00030 00031 namespace gr { 00032 namespace filter { 00033 00034 /*! 00035 * \brief single pole IIR filter with float input, float output 00036 * \ingroup filter_blk 00037 * 00038 * \details 00039 * The input and output satisfy a difference equation of the form 00040 \htmlonly 00041 \f{ 00042 y[n] - (1-alpha) y[n-1] = alpha x[n] 00043 \f} 00044 \endhtmlonly 00045 00046 \xmlonly 00047 y[n] - (1-alpha) y[n-1] = alpha x[n] 00048 \endxmlonly 00049 00050 * with the corresponding rational system function 00051 \htmlonly 00052 \f{ 00053 H(z) = \frac{alpha}{1 - (1-alpha) z^{-1}} 00054 \f} 00055 \endhtmlonly 00056 00057 \xmlonly 00058 H(z) = \ frac{alpha}{1 - (1-alpha) z^{-1}} 00059 \endxmlonly 00060 00061 * Note that some texts define the system function with a + in the 00062 * denominator. If you're using that convention, you'll need to 00063 * negate the feedback tap. 00064 */ 00065 class FILTER_API single_pole_iir_filter_ff : virtual public sync_block 00066 { 00067 public: 00068 // gr::filter::single_pole_iir_filter_ff::sptr 00069 typedef boost::shared_ptr<single_pole_iir_filter_ff> sptr; 00070 00071 static sptr make(double alpha, unsigned int vlen=1); 00072 00073 virtual void set_taps (double alpha) = 0; 00074 }; 00075 00076 } /* namespace filter */ 00077 } /* namespace gr */ 00078 00079 #endif /* INCLUDED_SINGLE_POLE_IIR_FILTER_FF_H */