sdrangel/plugins/channelrx/demodnfm/nfmdemodsink.h

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2019 Edouard Griffiths, F4EXB                                   //
//                                                                               //
// 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_NFMDEMODSINK_H
#define INCLUDE_NFMDEMODSINK_H

#include <QVector>

#include "dsp/channelsamplesink.h"
#include "dsp/phasediscri.h"
#include "dsp/nco.h"
#include "dsp/interpolator.h"
#include "dsp/fftfilt.h"
#include "dsp/firfilter.h"
#include "dsp/afsquelch.h"
#include "dsp/agc.h"
#include "dsp/ctcssdetector.h"
#include "util/movingaverage.h"
#include "util/doublebufferfifo.h"
#include "audio/audiofifo.h"

#include "nfmdemodsettings.h"

class ChannelAPI;

class NFMDemodSink : public ChannelSampleSink {
public:
    NFMDemodSink();

    virtual void feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end);

    const Real *getCtcssToneSet(int& nbTones) const {
        nbTones = m_ctcssDetector.getNTones();
        return m_ctcssDetector.getToneSet();
    }

    void setSelectedCtcssIndex(int selectedCtcssIndex) {
        m_ctcssIndexSelected = selectedCtcssIndex;
    }

    bool getSquelchOpen() const { return m_squelchOpen; }

    void getMagSqLevels(double& avg, double& peak, int& nbSamples)
    {
        if (m_magsqCount > 0)
        {
            m_magsq = m_magsqSum / m_magsqCount;
            m_magSqLevelStore.m_magsq = m_magsq;
            m_magSqLevelStore.m_magsqPeak = m_magsqPeak;
        }

        avg = m_magSqLevelStore.m_magsq;
        peak = m_magSqLevelStore.m_magsqPeak;
        nbSamples = m_magsqCount == 0 ? 1 : m_magsqCount;

        m_magsqSum = 0.0f;
        m_magsqPeak = 0.0f;
        m_magsqCount = 0;
    }

    void applyChannelSettings(int channelSampleRate, int channelFrequencyOffset, bool force = false);
    void applySettings(const NFMDemodSettings& settings, bool force = false);
    void setMessageQueueToGUI(MessageQueue *messageQueue) { m_messageQueueToGUI = messageQueue; }

    AudioFifo *getAudioFifo() { return &m_audioFifo; }
    void applyAudioSampleRate(unsigned int sampleRate);
    int getAudioSampleRate() const { return m_audioSampleRate; }
    void setChannel(ChannelAPI *channel) { m_channel = channel; }

private:
    struct MagSqLevelsStore
    {
        MagSqLevelsStore() :
            m_magsq(1e-12),
            m_magsqPeak(1e-12)
        {}
        double m_magsq;
        double m_magsqPeak;
    };

    enum RateState {
        RSInitialFill,
        RSRunning
    };

    int m_channelSampleRate;
    int m_channelFrequencyOffset;
    NFMDemodSettings m_settings;
    ChannelAPI *m_channel;

    int m_audioSampleRate;
    AudioVector m_audioBuffer;
    uint m_audioBufferFill;
    AudioFifo m_audioFifo;
    QVector<qint16> m_demodBuffer;
    int m_demodBufferFill;

    NCO m_nco;
    Interpolator m_interpolator;
    fftfilt m_rfFilter;
    Real m_interpolatorDistance;
    Real m_interpolatorDistanceRemain;
    Lowpass<Real> m_ctcssLowpass;
    Bandpass<Real> m_bandpass;
    Lowpass<Real> m_lowpass;
    CTCSSDetector m_ctcssDetector;
    int m_ctcssIndex; // 0 for nothing detected
    int m_ctcssIndexSelected;
    int m_sampleCount;
    int m_squelchCount;
    int m_squelchGate;
    int m_filterTaps;

    Real m_squelchLevel;
    bool m_squelchOpen;
    bool m_afSquelchOpen;
    double m_magsq; //!< displayed averaged value
    double m_magsqSum;
    double m_magsqPeak;
    int  m_magsqCount;
    MagSqLevelsStore m_magSqLevelStore;

    MovingAverageUtil<Real, double, 32> m_movingAverage;
    AFSquelch m_afSquelch;
    DoubleBufferFIFO<Real> m_squelchDelayLine;

    PhaseDiscriminators m_phaseDiscri;
    MessageQueue *m_messageQueueToGUI;

    static const double afSqTones[];
    static const double afSqTones_lowrate[];
    static const unsigned FFT_FILTER_LENGTH;
    static const unsigned CTCSS_DETECTOR_RATE;

    void processOneSample(Complex &ci);
    MessageQueue *getMessageQueueToGUI() { return m_messageQueueToGUI; }
};

#endif // INCLUDE_NFMDEMODSINK_H