pwr_squelch_ff.h

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/* -*- c++ -*- */
/*
 * Copyright 2006,2012 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * GNU Radio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */
 
#ifndef INCLUDED_ANALOG_PWR_SQUELCH_FF_H
#define INCLUDED_ANALOG_PWR_SQUELCH_FF_H
 
#include <gnuradio/analog/api.h>
#include <gnuradio/analog/squelch_base_ff.h>
#include <cmath>
 
namespace gr {
namespace analog {
 
/*!
 * \brief gate or zero output when input power below threshold
 * \ingroup level_controllers_blk
 */
class ANALOG_API pwr_squelch_ff : public squelch_base_ff, virtual public block
{
protected:
    virtual void update_state(const float& in) = 0;
    virtual bool mute() const = 0;
 
public:
    // gr::analog::pwr_squelch_ff::sptr
    typedef boost::shared_ptr<pwr_squelch_ff> sptr;
 
    /*!
     * \brief Make power-based squelch block.
     *
     * \param db threshold (in dB) for power squelch
     * \param alpha Gain of averaging filter. Defaults to 0.0001.
     * \param ramp attack / release time in samples; a sinusodial ramp
     *             is used. set to 0 to disable.
     * \param gate if true, no output if no squelch tone.
     *             if false, output 0's if no squelch tone (default).
     *
     * The block will emit a tag with the key pmt::intern("squelch_sob")
     * with the value of pmt::PMT_NIL on the first item it passes, and with
     * the key pmt::intern("squelch:eob") on the last item it passes.
     */
    static sptr make(double db, double alpha = 0.0001, int ramp = 0, bool gate = false);
 
    virtual std::vector<float> squelch_range() const = 0;
 
    virtual double threshold() const = 0;
    virtual void set_threshold(double db) = 0;
    virtual void set_alpha(double alpha) = 0;
 
    virtual int ramp() const = 0;
    virtual void set_ramp(int ramp) = 0;
    virtual bool gate() const = 0;
    virtual void set_gate(bool gate) = 0;
    virtual bool unmuted() const = 0;
};
 
} /* namespace analog */
} /* namespace gr */
 
#endif /* INCLUDED_ANALOG_PWR_SQUELCH_FF_H */