kopia lustrzana https://github.com/OpenRTX/OpenRTX
133 wiersze
4.2 KiB
C++
133 wiersze
4.2 KiB
C++
/***************************************************************************
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* Copyright (C) 2021 - 2023 by Federico Amedeo Izzo IU2NUO, *
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* Niccolò Izzo IU2KIN *
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* Frederik Saraci IU2NRO *
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* Silvano Seva IU2KWO *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 3 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, see <http://www.gnu.org/licenses/> *
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***************************************************************************/
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#ifndef M17_MODULATOR_H
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#define M17_MODULATOR_H
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#ifndef __cplusplus
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#error This header is C++ only!
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#endif
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#include <audio_stream.h>
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#include <M17/PwmCompensator.hpp>
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#include <M17/M17Constants.hpp>
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#include <audio_path.h>
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#include <cstdint>
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#include <memory>
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#include <array>
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namespace M17
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{
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/**
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* Modulator device for M17 protocol.
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*/
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class M17Modulator
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{
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public:
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/**
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* Constructor.
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*/
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M17Modulator();
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/**
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* Destructor.
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*/
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~M17Modulator();
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/**
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* Allocate buffers for baseband audio generation and initialise modulator.
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*/
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void init();
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/**
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* Forcefully shutdown modulator and deallocate data buffers.
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*/
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void terminate();
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/**
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* Start baseband transmission and send an 80ms preamble.
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*/
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void start();
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/**
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* Generate and transmit the baseband signal obtained by 4FSK modulation of
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* a given block of data.
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*
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* @param frame: M17 frame to be sent.
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* @param isLast: flag signalling that current block is the last one being
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* transmitted.
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*/
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void send(const frame_t& frame);
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/**
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* Terminate baseband transmission.
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*/
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void stop();
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/**
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* Invert baseband signal phase before output.
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*
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* @param status: if set to true signal phase is inverted.
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*/
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void invertPhase(const bool status);
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private:
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/**
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* Generate baseband stream from symbol stream.
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*/
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void symbolsToBaseband();
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/**
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* Emit the baseband stream towards the output stage, platform dependent.
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*/
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void sendBaseband();
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static constexpr size_t M17_TX_SAMPLE_RATE = 48000;
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static constexpr size_t M17_SAMPLES_PER_SYMBOL = M17_TX_SAMPLE_RATE / M17_SYMBOL_RATE;
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static constexpr size_t M17_FRAME_SAMPLES = M17_FRAME_SYMBOLS * M17_SAMPLES_PER_SYMBOL;
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#ifdef PLATFORM_MOD17
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static constexpr float M17_RRC_GAIN = 15000.0f;
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static constexpr float M17_RRC_OFFSET = 11500.0f;
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#else
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static constexpr float M17_RRC_GAIN = 23000.0f;
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static constexpr float M17_RRC_OFFSET = 0.0f;
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#endif
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std::array< int8_t, M17_FRAME_SYMBOLS > symbols;
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std::unique_ptr< int16_t[] > baseband_buffer; ///< Buffer for baseband audio handling.
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stream_sample_t *idleBuffer; ///< Half baseband buffer, free for processing.
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streamId outStream; ///< Baseband output stream ID.
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pathId outPath; ///< Baseband output path ID.
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bool txRunning; ///< Transmission running.
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bool invPhase; ///< Invert signal phase
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#if defined(PLATFORM_MD3x0) || defined(PLATFORM_MDUV3x0)
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PwmCompensator pwmComp;
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#endif
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};
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} /* M17 */
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#endif /* M17_MODULATOR_H */
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