kopia lustrzana https://github.com/mobilinkd/NucleoTNC
137 wiersze
3.0 KiB
C++
137 wiersze
3.0 KiB
C++
// Copyright 2015 Mobilinkd LLC <rob@mobilinkd.com>
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// All rights reserved.
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#ifndef MOBILINKD__AFSK_DEMODULATOR_HPP_
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#define MOBILINKD__AFSK_DEMODULATOR_HPP_
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#include <arm_math.h>
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#include "AGC.hpp"
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#include "DelayLine.hpp"
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#include "AudioInput.hpp"
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#include "DigitalPLL.hpp"
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// #include "Filter.h"
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#include "HdlcDecoder.hpp"
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#include "Hysteresis.hpp"
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#include "FirFilter.hpp"
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#include "IirFilter.hpp"
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#include "NRZI.hpp"
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#include "GPIO.hpp"
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#include <algorithm>
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#include <functional>
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namespace mobilinkd { namespace tnc { namespace afsk1200 {
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#if 0
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const float b[] = {
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4.57519926037e-06,
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2.28759963018e-05,
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4.57519926037e-05,
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4.57519926037e-05,
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2.28759963018e-05,
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4.57519926037e-06,
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};
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const float a[] = {
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1.0,
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-4.41489189545,
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7.82710410154,
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-6.96306748269,
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3.10736843037,
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-0.556366747391,
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};
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// Bessel 760Hz
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const float b[] = {
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4.36034607e-06,
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2.18017304e-05,
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4.36034607e-05,
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4.36034607e-05,
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2.18017304e-05,
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4.36034607e-06,
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};
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const float a[] = {
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1.0,
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-4.32673235,
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7.51393353,
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-6.54579279,
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2.86009139,
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-0.50136025,
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};
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#endif
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// Bessel 1200Hz 7-pole low-pass
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const float b[] = {
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6.10481382e-07,
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4.27336967e-06,
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1.28201090e-05,
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2.13668484e-05,
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2.13668484e-05,
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1.28201090e-05,
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4.27336967e-06,
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6.10481382e-07,
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};
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const float a[] = {
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1.0,
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-5.56209875,
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13.34528507,
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-17.89828744,
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14.48661262,
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-7.07391246,
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1.92904679,
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-0.22656769,
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};
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typedef FirFilter<audio::ADC_BUFFER_SIZE, 9> emphasis_filter_type;
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// typedef IirFilter<audio::ADC_BUFFER_SIZE, 2> emphasis_filter_type;
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struct Demodulator {
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typedef float float_type;
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typedef std::function<float_type(float_type)> filter_function_type;
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static const size_t SYMBOL_RATE = 1200;
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static const size_t BUFFER_SIZE = 330;
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typedef BaseDigitalPLL<float_type> DPLL;
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size_t sample_rate_;
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emphasis_filter_type& audio_filter_;
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libafsk::BaseAGC<float_type> agc_;
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libafsk::BlockHysteresis<bool, audio::ADC_BUFFER_SIZE> input_comparator_;
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libafsk::FixedDelayLine<40> delay_line_;
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IirFilter<8> correlator_filter_;
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libafsk::BaseHysteresis<float_type> output_comparator_;
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DPLL pll_;
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libafsk::NRZI nrzi_;
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hdlc::Decoder hdlc_decoder_;
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bool locked_;
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float_type buffer_a[audio::ADC_BUFFER_SIZE];
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Demodulator(size_t sample_rate, emphasis_filter_type& c)
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: sample_rate_(sample_rate)
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, audio_filter_(c)
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, agc_(.01, .001, 0.3, 1000.0)
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, input_comparator_(-0.0005, 0.0005)
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, delay_line_(sample_rate, 0.000448)
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, correlator_filter_(b, a)
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, output_comparator_(-0.05, 0.05)
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, pll_(sample_rate, SYMBOL_RATE)
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, nrzi_(), hdlc_decoder_(false), locked_(false)
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{}
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// hdlc::IoFrame* operator()(float* samples, size_t len) __attribute__((section(".bss2")));
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hdlc::IoFrame* operator()(float* samples, size_t len);
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bool locked() const {return locked_;}
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};
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}}} // mobilinkd::tnc::afsk1200
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#endif // MOBILINKD__AFSK_DEMODULATOR_HPP_
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