158 lines
4.7 KiB
C++
158 lines
4.7 KiB
C++
/***************************************************************************
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* Copyright (C) 2021 - 2022 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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#include <new>
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#include <dsp.h>
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#include <cstddef>
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#include <cstring>
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#include <experimental/array>
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#include <M17/M17Modulator.h>
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#include <M17/M17DSP.h>
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#if defined(PLATFORM_LINUX)
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#include <stdio.h>
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#endif
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using namespace M17;
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M17Modulator::M17Modulator()
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{
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}
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M17Modulator::~M17Modulator()
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{
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terminate();
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}
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void M17Modulator::init()
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{
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/*
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* Allocate a chunk of memory to contain two complete buffers for baseband
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* audio. Split this chunk in two separate blocks for double buffering using
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* placement new.
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*/
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baseband_buffer = new int16_t[2 * M17_FRAME_SAMPLES_48K];
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idleBuffer = baseband_buffer;
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txRunning = false;
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}
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void M17Modulator::terminate()
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{
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// Deallocate memory.
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delete[] baseband_buffer;
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}
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void M17Modulator::send(const std::array< uint8_t, 2 >& sync,
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const std::array< uint8_t, 46 >& data,
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const bool isLast)
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{
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auto sync1 = byteToSymbols(sync[0]);
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auto sync2 = byteToSymbols(sync[1]);
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auto it = std::copy(sync1.begin(), sync1.end(), symbols.begin());
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it = std::copy(sync2.begin(), sync2.end(), it);
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for(size_t i = 0; i < data.size(); i++)
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{
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auto sym = byteToSymbols(data[i]);
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it = std::copy(sym.begin(), sym.end(), it);
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}
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// If last frame, signal stop of transmission
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if(isLast) stopTx = true;
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generateBaseband();
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emitBaseband();
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}
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void M17Modulator::generateBaseband()
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{
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memset(idleBuffer, 0x00, M17_FRAME_SAMPLES_48K * sizeof(stream_sample_t));
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for(size_t i = 0; i < symbols.size(); i++)
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{
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idleBuffer[i * 10] = symbols[i];
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}
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for(size_t i = 0; i < M17_FRAME_SAMPLES_48K; i++)
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{
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float elem = static_cast< float >(idleBuffer[i]);
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idleBuffer[i] = static_cast< int16_t >((M17::rrc(elem) * M17_RRC_GAIN)
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- M17_RRC_OFFSET);
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}
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}
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#ifndef PLATFORM_LINUX
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void M17Modulator::emitBaseband()
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{
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#if defined(PLATFORM_MD3x0) || defined(PLATFORM_MDUV3x0)
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dsp_pwmCompensate(idleBuffer, M17_FRAME_SAMPLES_48K);
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dsp_invertPhase(idleBuffer, M17_FRAME_SAMPLES_48K);
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#endif
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if(txRunning == false)
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{
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// First run, start transmission
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outStream = outputStream_start(SINK_RTX,
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PRIO_TX,
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baseband_buffer,
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2*M17_FRAME_SAMPLES_48K,
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BUF_CIRC_DOUBLE,
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M17_TX_SAMPLE_RATE);
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txRunning = true;
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stopTx = false;
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}
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else
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{
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// Transmission is ongoing, syncronise with stream end before proceeding
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outputStream_sync(outStream, true);
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}
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// Check if transmission stop is requested
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if(stopTx == true)
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{
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outputStream_stop(outStream);
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stopTx = false;
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txRunning = false;
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idleBuffer = baseband_buffer;
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}
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else
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{
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idleBuffer = outputStream_getIdleBuffer(outStream);
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}
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}
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#else
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void M17Modulator::emitBaseband()
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{
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FILE *outfile = fopen("/tmp/m17_output.raw", "ab");
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for(size_t i = 0; i < M17_FRAME_SAMPLES_48K; i++)
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{
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auto s = idleBuffer[i];
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fwrite(&s, sizeof(s), 1, outfile);
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}
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fclose(outfile);
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}
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#endif
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