sdrangel/plugins/channeltx/modais/aismodsource.h

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C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2019 Edouard Griffiths, F4EXB //
// Copyright (C) 2020 Jon Beniston, M7RCE //
// //
// This program 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 as version 3 of the License, or //
// (at your option) any later version. //
// //
// This program 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 V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////
#ifndef INCLUDE_AISMODSOURCE_H
#define INCLUDE_AISMODSOURCE_H
#include <QMutex>
#include <QDebug>
#include <QVector>
#include <iostream>
#include <fstream>
#include "dsp/channelsamplesource.h"
#include "dsp/nco.h"
#include "dsp/ncof.h"
#include "dsp/interpolator.h"
#include "dsp/firfilter.h"
#include "dsp/gaussian.h"
#include "util/movingaverage.h"
#include "aismodsettings.h"
// Train, flag, data, crc, flag and a zero for ramp down. Longest message is 1008/8=126 bytes
#define AIS_MAX_BYTES (3+1+126+2+1+1)
// Add extra space for bit stuffing
#define AIS_MAX_BITS (AIS_MAX_BYTES*2)
#define AIS_TRAIN 0x55
#define AIS_FLAG 0x7e
class ScopeVis;
class BasebandSampleSink;
class ChannelAPI;
class AISModSource : public ChannelSampleSource
{
public:
AISModSource();
virtual ~AISModSource();
virtual void pull(SampleVector::iterator begin, unsigned int nbSamples);
virtual void pullOne(Sample& sample);
virtual void prefetch(unsigned int nbSamples) { (void) nbSamples; }
double getMagSq() const { return m_magsq; }
void getLevels(qreal& rmsLevel, qreal& peakLevel, int& numSamples) const
{
rmsLevel = m_rmsLevel;
peakLevel = m_peakLevelOut;
numSamples = m_levelNbSamples;
}
void setSpectrumSink(BasebandSampleSink *sampleSink) { m_spectrumSink = sampleSink; }
void setScopeSink(ScopeVis* scopeSink) { m_scopeSink = scopeSink; }
void applySettings(const AISModSettings& settings, bool force = false);
void applyChannelSettings(int channelSampleRate, int channelFrequencyOffset, bool force = false);
void addTXPacket(const QString& data);
void addTXPacket(QByteArray data);
void encodePacket(uint8_t *packet, int packet_length, uint8_t *crc_start, uint8_t *packet_end);
void setChannel(ChannelAPI *channel) { m_channel = channel; }
void transmit();
private:
int m_channelSampleRate;
int m_channelFrequencyOffset;
AISModSettings m_settings;
ChannelAPI *m_channel;
NCO m_carrierNco;
double m_fmPhase; // Double gives cleaner spectrum than Real
double m_phaseSensitivity;
Real m_linearGain;
Complex m_modSample;
int m_nrziBit; // Output of NRZI coder
Gaussian<Real> m_pulseShape; // Pulse shaping filter
BasebandSampleSink* m_spectrumSink; // Spectrum GUI to display baseband waveform
ScopeVis* m_scopeSink; // Scope GUI to display baseband waveform
Interpolator m_interpolator; // Interpolator to channel sample rate
Real m_interpolatorDistance;
Real m_interpolatorDistanceRemain;
double m_magsq;
MovingAverageUtil<double, double, 16> m_movingAverage;
quint32 m_levelCalcCount;
qreal m_rmsLevel;
qreal m_peakLevelOut;
Real m_peakLevel;
Real m_levelSum;
static const int m_levelNbSamples = 480; // every 10ms assuming 48k Sa/s
int m_sampleIdx; // Sample index in to symbol
int m_samplesPerSymbol; // Number of samples per symbol
Real m_pow; // In dB
Real m_powRamp; // In dB
enum AISModState {
idle, ramp_up, tx, ramp_down, wait
} m_state; // States for sample modulation
int m_packetRepeatCount;
uint64_t m_waitCounter; // Samples to wait before retransmission
uint8_t m_bits[AIS_MAX_BITS]; // HDLC encoded bits to transmit
int m_byteIdx; // Index in to m_bits
int m_bitIdx; // Index in to current byte of m_bits
int m_last5Bits; // Last 5 bits to be HDLC encoded
int m_bitCount; // Count of number of valid bits in m_bits
int m_bitCountTotal;
std::ofstream m_iqFile; // For debug output of baseband waveform
QVector<qint16> m_demodBuffer;
int m_demodBufferFill;
SampleVector m_scopeSampleBuffer;
static const int m_scopeSampleBufferSize = AISModSettings::AISMOD_SAMPLE_RATE / 20;
int m_scopeSampleBufferIndex;
SampleVector m_specSampleBuffer;
static const int m_specSampleBufferSize = 1024;
int m_specSampleBufferIndex;
bool bitsValid(); // Are there and bits to transmit
int getBit(); // Get bit from m_bits
void addBit(int bit); // Add bit to m_bits, with zero stuffing
void initTX();
void calculateLevel(Real& sample);
void modulateSample();
void sampleToSpectrum(Complex sample);
void sampleToScope(Complex sample);
};
#endif // INCLUDE_AISMODSOURCE_H