hamnet70-gnuradio-legacy/gr-hamnet70/lib/correct_frequency_impl.h
Thomas Kolb cd9784efb6 Added frequency estimator blocks
- correct_frequency: Correct frequency by averaging the phase drift on
                     the preamble
- freq_est_lr: Luise & Reggiannini frequency estimator
- pid_controller: a PID controller that takes error values at the input
                  and generates steering values at the output

The combination of freq_est_lr and PID controller can be used together
with an NCO (signal source) to create a closed control loop for
frequency offset compensation.
2019-07-23 23:16:48 +02:00

58 lines
1.7 KiB
C++

/* -*- c++ -*- */
/*
* Copyright 2019 Thomas Kolb.
*
* This 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.
*
* This software 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 this software; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef INCLUDED_HAMNET70_CORRECT_FREQUENCY_IMPL_H
#define INCLUDED_HAMNET70_CORRECT_FREQUENCY_IMPL_H
#include <hamnet70/correct_frequency.h>
namespace gr {
namespace hamnet70 {
class correct_frequency_impl : public correct_frequency
{
private:
std::vector<gr_complex> d_symbols;
gr_complex d_correctionVector;
gr_complex d_correctionIncrement;
float d_lastPhase;
float d_filteredPhaseInc;
float d_unwrapOffset;
size_t d_preIdx;
static const constexpr float c_phaseInc_alpha = 0.001f;
public:
correct_frequency_impl(const std::vector<gr_complex> &symbols);
~correct_frequency_impl();
// Where all the action really happens
int work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items);
};
} // namespace hamnet70
} // namespace gr
#endif /* INCLUDED_HAMNET70_CORRECT_FREQUENCY_IMPL_H */