sdrangel/plugins/channel/demoddsd/dsddemod.cpp

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2015 F4EXB                                                      //
// written by Edouard Griffiths                                                  //
//                                                                               //
// 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                  //
//                                                                               //
// 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/>.          //
///////////////////////////////////////////////////////////////////////////////////

#include <QTime>
#include <QDebug>
#include <stdio.h>
#include <complex.h>
#include "dsddemod.h"
#include "dsddemodgui.h"
#include "audio/audiooutput.h"
#include "dsp/channelizer.h"
#include "dsp/pidcontroller.h"
#include "dsp/dspengine.h"

static const Real afSqTones[2] = {1200.0, 6400.0}; // {1200.0, 8000.0};

MESSAGE_CLASS_DEFINITION(DSDDemod::MsgConfigureDSDDemod, Message)

DSDDemod::DSDDemod(SampleSink* sampleSink) :
	m_sampleCount(0),
	m_squelchCount(0),
	m_squelchOpen(false),
	m_audioFifo(4, 48000),
	m_fmExcursion(24),
	m_settingsMutex(QMutex::Recursive),
    m_scope(sampleSink),
	m_scopeEnabled(true),
	m_dsdDecoder()
{
	setObjectName("DSDDemod");

	m_dsdInBuffer = new qint16[1<<18]; // 128 k Samples is the maximum size of all input devices sample buffers (Airspy or HackRF) = 2^(17+1) for 2 byte samples

	m_config.m_inputSampleRate = 96000;
	m_config.m_inputFrequencyOffset = 0;
	m_config.m_rfBandwidth = 100;
	m_config.m_demodGain = 100;
	m_config.m_fmDeviation = 100;
	m_config.m_squelchGate = 5; // 10s of ms at 48000 Hz sample rate. Corresponds to 2400 for AGC attack
	m_config.m_squelch = -30.0;
	m_config.m_volume = 1.0;
	m_config.m_audioMute = false;
	m_config.m_audioSampleRate = DSPEngine::instance()->getAudioSampleRate();

	apply();

	m_audioBuffer.resize(1<<14);
	m_audioBufferFill = 0;

    m_movingAverage.resize(16, 0);

	DSPEngine::instance()->addAudioSink(&m_audioFifo);
}

DSDDemod::~DSDDemod()
{
	DSPEngine::instance()->removeAudioSink(&m_audioFifo);
	delete[] m_dsdInBuffer;
}

void DSDDemod::configure(MessageQueue* messageQueue,
		int  rfBandwidth,
		int  demodGain,
		int  fmDeviation,
		int  volume,
		int  squelchGate,
		Real squelch,
		bool audioMute)
{
	Message* cmd = MsgConfigureDSDDemod::create(rfBandwidth,
			demodGain,
			fmDeviation,
			volume,
			squelchGate,
			squelch,
			audioMute);
	messageQueue->push(cmd);
}

void DSDDemod::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end, bool firstOfBurst)
{
	Complex ci;

	m_settingsMutex.lock();
	m_dsdInCount = 0;
	m_scopeSampleBuffer.clear();

	for (SampleVector::const_iterator it = begin; it != end; ++it)
	{
		Complex c(it->real(), it->imag());
		c *= m_nco.nextIQ();

        if (m_interpolator.interpolate(&m_interpolatorDistanceRemain, c, &ci))
        {
            qint16 sample;

            m_magsq = ((ci.real()*ci.real() +  ci.imag()*ci.imag())) / (Real) (1<<30);
            m_movingAverage.feed(m_magsq);

            Real demod = 32768.0f * m_phaseDiscri.phaseDiscriminator(ci) * ((float) m_running.m_demodGain / 100.0f);
            m_sampleCount++;

            // AF processing

            if (getMagSq() > m_squelchLevel)
            {
                if (m_squelchCount < m_squelchGate)
                {
                    m_squelchCount++;
                }
            }
            else
            {
                m_squelchCount = 0;
            }

            m_squelchOpen = m_squelchCount == m_squelchGate;

            if (m_squelchOpen)
            {
                sample = demod;
            }
            else
            {
                sample = 0;
            }

            Sample s(sample, 0.0);
            m_scopeSampleBuffer.push_back(s);
            m_dsdInBuffer[m_dsdInCount++] = sample;

//				if (m_running.m_audioMute)
//				{
//	                m_audioBuffer[m_audioBufferFill].l = 0;
//	                m_audioBuffer[m_audioBufferFill].r = 0;
//				}
//				else
//				{
//	                m_audioBuffer[m_audioBufferFill].l = sample;
//	                m_audioBuffer[m_audioBufferFill].r = sample;
//				}
//
//				++m_audioBufferFill;
//
//				if (m_audioBufferFill >= m_audioBuffer.size())
//				{
//					uint res = m_audioFifo.write((const quint8*)&m_audioBuffer[0], m_audioBufferFill, 10);
//
//					if (res != m_audioBufferFill)
//					{
//						qDebug("DSDDemod::feed: %u/%u audio samples written", res, m_audioBufferFill);
//					}
//
//					m_audioBufferFill = 0;
//				}

            m_interpolatorDistanceRemain += m_interpolatorDistance;
        }
	}


//	if (m_audioBufferFill > 0)
//	{
//		uint res = m_audioFifo.write((const quint8*)&m_audioBuffer[0], m_audioBufferFill, 10);
//
//		if (res != m_audioBufferFill)
//		{
//			qDebug("NFMDemod::feed: %u/%u tail samples written", res, m_audioBufferFill);
//		}
//
//		m_audioBufferFill = 0;
//	}

	m_dsdDecoder.popAudioSamples(&m_audioFifo, m_running.m_audioMute);
    m_dsdDecoder.pushSamples(m_dsdInBuffer, m_dsdInCount);

    if ((m_scope != 0) && (m_scopeEnabled))
    {
        m_scope->feed(m_scopeSampleBuffer.begin(), m_scopeSampleBuffer.end(), true); // true = real samples for what it's worth
    }

	m_settingsMutex.unlock();
}

void DSDDemod::start()
{
	m_audioFifo.clear();
	m_phaseDiscri.reset();
	m_dsdDecoder.start();
}

void DSDDemod::stop()
{
    m_dsdDecoder.stop();
}

bool DSDDemod::handleMessage(const Message& cmd)
{
	qDebug() << "DSDDemod::handleMessage";

	if (Channelizer::MsgChannelizerNotification::match(cmd))
	{
		Channelizer::MsgChannelizerNotification& notif = (Channelizer::MsgChannelizerNotification&) cmd;

		m_config.m_inputSampleRate = notif.getSampleRate();
		m_config.m_inputFrequencyOffset = notif.getFrequencyOffset();

		apply();

		qDebug() << "DSDDemod::handleMessage: MsgChannelizerNotification: m_inputSampleRate: " << m_config.m_inputSampleRate
				<< " m_inputFrequencyOffset: " << m_config.m_inputFrequencyOffset;

		return true;
	}
	else if (MsgConfigureDSDDemod::match(cmd))
	{
		MsgConfigureDSDDemod& cfg = (MsgConfigureDSDDemod&) cmd;

		m_config.m_rfBandwidth = cfg.getRFBandwidth();
		m_config.m_demodGain = cfg.getDemodGain();
		m_config.m_fmDeviation = cfg.getFMDeviation();
		m_config.m_volume = cfg.getVolume();
		m_config.m_squelchGate = cfg.getSquelchGate();
		m_config.m_squelch = cfg.getSquelch();
		m_config.m_audioMute = cfg.getAudioMute();

		apply();

		qDebug() << "DSDDemod::handleMessage: MsgConfigureDSDDemod: m_rfBandwidth: " << m_config.m_rfBandwidth * 100
				<< " m_demodGain: " << m_config.m_demodGain / 100.0
				<< " m_fmDeviation: " << m_config.m_fmDeviation * 100
				<< " m_volume: " << m_config.m_volume / 10.0
				<< " m_squelchGate" << m_config.m_squelchGate
				<< " m_squelch: " << m_config.m_squelch
				<< " m_audioMute: " << m_config.m_audioMute;

		return true;
	}
	else
	{
		return false;
	}
}

void DSDDemod::apply()
{
	if ((m_config.m_inputFrequencyOffset != m_running.m_inputFrequencyOffset) ||
		(m_config.m_inputSampleRate != m_running.m_inputSampleRate))
	{
		m_nco.setFreq(-m_config.m_inputFrequencyOffset, m_config.m_inputSampleRate);
	}

	if ((m_config.m_inputSampleRate != m_running.m_inputSampleRate) ||
		(m_config.m_rfBandwidth != m_running.m_rfBandwidth))
	{
		m_settingsMutex.lock();
		m_interpolator.create(16, m_config.m_inputSampleRate, (m_config.m_rfBandwidth * 100) / 2.2);
		m_interpolatorDistanceRemain = 0;
		m_interpolatorDistance =  (Real) m_config.m_inputSampleRate / (Real) m_config.m_audioSampleRate;
		m_phaseDiscri.setFMScaling((float) m_config.m_rfBandwidth / (float) m_config.m_fmDeviation);
		m_settingsMutex.unlock();
	}

	if (m_config.m_fmDeviation != m_running.m_fmDeviation)
	{
		m_phaseDiscri.setFMScaling((float) m_config.m_rfBandwidth / (float) m_config.m_fmDeviation);
	}

	if (m_config.m_squelchGate != m_running.m_squelchGate)
	{
		m_squelchGate = 480 * m_config.m_squelchGate; // gate is given in 10s of ms at 48000 Hz audio sample rate
	}

	if (m_config.m_squelch != m_running.m_squelch)
	{
		// input is a value in tenths of dB
		m_squelchLevel = std::pow(10.0, m_config.m_squelch / 100.0);
		//m_squelchLevel *= m_squelchLevel;
	}

	m_running.m_inputSampleRate = m_config.m_inputSampleRate;
	m_running.m_inputFrequencyOffset = m_config.m_inputFrequencyOffset;
	m_running.m_rfBandwidth = m_config.m_rfBandwidth;
	m_running.m_demodGain = m_config.m_demodGain;
	m_running.m_fmDeviation = m_config.m_fmDeviation;
	m_running.m_squelchGate = m_config.m_squelchGate;
	m_running.m_squelch = m_config.m_squelch;
	m_running.m_volume = m_config.m_volume;
	m_running.m_audioSampleRate = m_config.m_audioSampleRate;
	m_running.m_audioMute = m_config.m_audioMute;
}