GNU Radio 3.4.0 C++ API
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00001 /* -*- c++ -*- */ 00002 /* 00003 * Copyright 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_PWR_SQUELCH_FF_H 00024 #define INCLUDED_GR_PWR_SQUELCH_FF_H 00025 00026 #include <cmath> 00027 #include <gr_squelch_base_ff.h> 00028 #include <gr_single_pole_iir.h> 00029 00030 class gr_pwr_squelch_ff; 00031 typedef boost::shared_ptr<gr_pwr_squelch_ff> gr_pwr_squelch_ff_sptr; 00032 00033 gr_pwr_squelch_ff_sptr 00034 gr_make_pwr_squelch_ff(double db, double alpha = 0.0001, int ramp=0, bool gate=false); 00035 00036 /*! 00037 * \brief gate or zero output when input power below threshold 00038 * \ingroup level_blk 00039 */ 00040 class gr_pwr_squelch_ff : public gr_squelch_base_ff 00041 { 00042 private: 00043 double d_threshold; 00044 double d_pwr; 00045 gr_single_pole_iir<double,double,double> d_iir; 00046 00047 friend gr_pwr_squelch_ff_sptr gr_make_pwr_squelch_ff(double db, double alpha, int ramp, bool gate); 00048 gr_pwr_squelch_ff(double db, double alpha, int ramp, bool gate); 00049 00050 protected: 00051 virtual void update_state(const float &in); 00052 virtual bool mute() const { return d_pwr < d_threshold; } 00053 00054 public: 00055 std::vector<float> squelch_range() const; 00056 00057 double threshold() const { return 10*log10(d_threshold); } 00058 void set_threshold(double db) { d_threshold = std::pow(10.0, db/10); } 00059 void set_alpha(double alpha) { d_iir.set_taps(alpha); } 00060 }; 00061 00062 #endif /* INCLUDED_GR_PWR_SQUELCH_FF_H */