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/* -*- C++ -*- */
/*
* Copyright 2006, 2007 Frank (Radio Rausch)
* Copyright 2011 Steve Glass
*
* This file is part of OP25.
*
* OP25 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.
*
* OP25 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 OP25; see the file COPYING. If not, write to the Free
* Software Foundation, Inc., 51 Franklin Street, Boston, MA
* 02110-1301, USA.
*/
#ifndef INCLUDED_OP25_FSK4_DEMOD_FF_H
#define INCLUDED_OP25_FSK4_DEMOD_FF_H
#include <gr_block.h>
#include <gr_msg_queue.h>
#include <boost/scoped_array.hpp>
typedef boost::shared_ptr<class op25_fsk4_demod_ff> op25_fsk4_demod_ff_sptr;
op25_fsk4_demod_ff_sptr op25_make_fsk4_demod_ff(gr_msg_queue_sptr queue, float sample_rate, float symbol_rate);
/**
* op25_fsk4_demod_ff is a GNU Radio block for demodulating APCO P25
* CF4M signals. This class expects its input to consist of a 4 level
* FSK modulated baseband signal. It produces a stream of symbols.
*
* All inputs are post FM demodulator and symbol shaping filter data
* is normalized before being sent to this block so these parameters
* should not need adjusting even when working on different signals.
*
* Nominal levels are -3, -1, +1, and +3.
*/
class op25_fsk4_demod_ff : public gr_block
{
public:
/**
* op25_fsk4_demod_ff (virtual) destructor.
*/
virtual ~op25_fsk4_demod_ff();
/**
* Estimate nof_input_items_reqd for a given nof_output_items.
*/
virtual void forecast(int noutput_items, gr_vector_int &inputs_required);
/**
* Process baseband into symbols.
*/
virtual int general_work(int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items);
private:
/**
* Expose class to public ctor. Create a new instance of
* op25_fsk4_demod_ff and wrap it in a shared_ptr. This is
* effectively the public constructor.
*/
friend op25_fsk4_demod_ff_sptr op25_make_fsk4_demod_ff(gr_msg_queue_sptr queue, float sample_rate, float symbol_rate);
/**
* op25_fsk4_demod_ff private constructor.
*/
op25_fsk4_demod_ff(gr_msg_queue_sptr queue, float sample_rate, float symbol_rate);
/**
* Called when we want the input frequency to be adjusted.
*/
void send_frequency_correction();
/**
* Tracking loop.
*/
bool tracking_loop_mmse(float input, float *output);
private:
const float d_block_rate;
boost::scoped_array<float> d_history;
size_t d_history_last;
gr_msg_queue_sptr d_queue;
double d_symbol_clock;
double d_symbol_spread;
const float d_symbol_time;
double fine_frequency_correction;
double coarse_frequency_correction;
};
#endif /* INCLUDED_OP25_FSK4_DEMOD_FF_H */
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