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https://github.com/f4exb/sdrangel.git
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153 lines
5.9 KiB
C++
153 lines
5.9 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2019 Edouard Griffiths, F4EXB //
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// Copyright (C) 2020 Jon Beniston, M7RCE //
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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 as 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 V3 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 INCLUDE_AISMODSOURCE_H
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#define INCLUDE_AISMODSOURCE_H
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#include <QMutex>
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#include <QDebug>
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#include <QVector>
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#include <iostream>
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#include <fstream>
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#include "dsp/channelsamplesource.h"
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#include "dsp/nco.h"
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#include "dsp/ncof.h"
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#include "dsp/interpolator.h"
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#include "dsp/firfilter.h"
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#include "dsp/gaussian.h"
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#include "util/movingaverage.h"
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#include "aismodsettings.h"
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// Train, flag, data, crc, flag and a zero for ramp down. Longest message is 1008/8=126 bytes
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#define AIS_MAX_BYTES (3+1+126+2+1+1)
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// Add extra space for bit stuffing
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#define AIS_MAX_BITS (AIS_MAX_BYTES*2)
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#define AIS_TRAIN 0x55
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#define AIS_FLAG 0x7e
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class ScopeVis;
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class BasebandSampleSink;
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class ChannelAPI;
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class AISModSource : public ChannelSampleSource
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{
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public:
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AISModSource();
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virtual ~AISModSource();
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virtual void pull(SampleVector::iterator begin, unsigned int nbSamples);
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virtual void pullOne(Sample& sample);
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virtual void prefetch(unsigned int nbSamples) { (void) nbSamples; }
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double getMagSq() const { return m_magsq; }
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void getLevels(qreal& rmsLevel, qreal& peakLevel, int& numSamples) const
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{
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rmsLevel = m_rmsLevel;
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peakLevel = m_peakLevelOut;
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numSamples = m_levelNbSamples;
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}
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void setSpectrumSink(BasebandSampleSink *sampleSink) { m_spectrumSink = sampleSink; }
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void setScopeSink(ScopeVis* scopeSink) { m_scopeSink = scopeSink; }
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void applySettings(const AISModSettings& settings, bool force = false);
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void applyChannelSettings(int channelSampleRate, int channelFrequencyOffset, bool force = false);
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void addTXPacket(const QString& data);
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void addTXPacket(QByteArray data);
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void encodePacket(uint8_t *packet, int packet_length, uint8_t *crc_start, uint8_t *packet_end);
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void setChannel(ChannelAPI *channel) { m_channel = channel; }
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void transmit();
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private:
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int m_channelSampleRate;
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int m_channelFrequencyOffset;
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AISModSettings m_settings;
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ChannelAPI *m_channel;
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NCO m_carrierNco;
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double m_fmPhase; // Double gives cleaner spectrum than Real
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double m_phaseSensitivity;
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Real m_linearGain;
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Complex m_modSample;
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int m_nrziBit; // Output of NRZI coder
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Gaussian<Real> m_pulseShape; // Pulse shaping filter
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BasebandSampleSink* m_spectrumSink; // Spectrum GUI to display baseband waveform
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ScopeVis* m_scopeSink; // Scope GUI to display baseband waveform
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Interpolator m_interpolator; // Interpolator to channel sample rate
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Real m_interpolatorDistance;
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Real m_interpolatorDistanceRemain;
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double m_magsq;
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MovingAverageUtil<double, double, 16> m_movingAverage;
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quint32 m_levelCalcCount;
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qreal m_rmsLevel;
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qreal m_peakLevelOut;
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Real m_peakLevel;
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Real m_levelSum;
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static const int m_levelNbSamples = 480; // every 10ms assuming 48k Sa/s
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int m_sampleIdx; // Sample index in to symbol
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int m_samplesPerSymbol; // Number of samples per symbol
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Real m_pow; // In dB
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Real m_powRamp; // In dB
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enum AISModState {
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idle, ramp_up, tx, ramp_down, wait
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} m_state; // States for sample modulation
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int m_packetRepeatCount;
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uint64_t m_waitCounter; // Samples to wait before retransmission
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uint8_t m_bits[AIS_MAX_BITS]; // HDLC encoded bits to transmit
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int m_byteIdx; // Index in to m_bits
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int m_bitIdx; // Index in to current byte of m_bits
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int m_last5Bits; // Last 5 bits to be HDLC encoded
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int m_bitCount; // Count of number of valid bits in m_bits
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int m_bitCountTotal;
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std::ofstream m_iqFile; // For debug output of baseband waveform
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QVector<qint16> m_demodBuffer;
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int m_demodBufferFill;
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SampleVector m_scopeSampleBuffer;
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static const int m_scopeSampleBufferSize = AISModSettings::AISMOD_SAMPLE_RATE / 20;
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int m_scopeSampleBufferIndex;
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SampleVector m_specSampleBuffer;
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static const int m_specSampleBufferSize = 1024;
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int m_specSampleBufferIndex;
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bool bitsValid(); // Are there and bits to transmit
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int getBit(); // Get bit from m_bits
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void addBit(int bit); // Add bit to m_bits, with zero stuffing
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void initTX();
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void calculateLevel(Real& sample);
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void modulateSample();
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void sampleToSpectrum(Complex sample);
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void sampleToScope(Complex sample);
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};
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#endif // INCLUDE_AISMODSOURCE_H
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