sdrangel/plugins/channelrx/demodwfm/wfmdemod.cpp

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2012 maintech GmbH, Otto-Hahn-Str. 15, 97204 Hoechberg, Germany //
// written by Christian Daniel                                                   //
//                                                                               //
// 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 "../../channelrx/demodwfm/wfmdemod.h"

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

MESSAGE_CLASS_DEFINITION(WFMDemod::MsgConfigureWFMDemod, Message)

WFMDemod::WFMDemod(BasebandSampleSink* sampleSink) :
    m_squelchOpen(false),
    m_magsq(0.0f),
    m_magsqSum(0.0f),
    m_magsqPeak(0.0f),
    m_magsqCount(0),
    m_movingAverage(40, 0),
    m_sampleSink(sampleSink),
    m_audioFifo(250000),
    m_settingsMutex(QMutex::Recursive)

{
	setObjectName("WFMDemod");

	m_config.m_inputSampleRate = 384000;
	m_config.m_inputFrequencyOffset = 0;
	m_config.m_rfBandwidth = 180000;
	m_config.m_afBandwidth = 15000;
	m_config.m_squelch = -60.0;
	m_config.m_volume = 2.0;
	m_config.m_audioSampleRate = DSPEngine::instance()->getAudioSampleRate();
	m_rfFilter = new fftfilt(-50000.0 / 384000.0, 50000.0 / 384000.0, rfFilterFftLength);
	m_phaseDiscri.setFMScaling(384000/75000);

	apply();

	m_audioBuffer.resize(16384);
	m_audioBufferFill = 0;

	m_movingAverage.resize(16, 0);

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

WFMDemod::~WFMDemod()
{
	if (m_rfFilter)
	{
		delete m_rfFilter;
	}

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

void WFMDemod::configure(
        MessageQueue* messageQueue,
        Real rfBandwidth,
        Real afBandwidth,
        Real volume,
        Real squelch,
        bool audioMute)
{
	Message* cmd = MsgConfigureWFMDemod::create(rfBandwidth, afBandwidth, volume, squelch, audioMute);
	messageQueue->push(cmd);
}

void WFMDemod::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end, bool firstOfBurst __attribute__((unused)))
{
	Complex ci;
	fftfilt::cmplx *rf;
	int rf_out;
	Real demod;
	double msq;
	float fmDev;

	m_settingsMutex.lock();

	for (SampleVector::const_iterator it = begin; it != end; ++it)
	{
		//Complex c(it->real() / 32768.0f, it->imag() / 32768.0f);
		Complex c(it->real(), it->imag());
		c *= m_nco.nextIQ();

		rf_out = m_rfFilter->runFilt(c, &rf); // filter RF before demod

		for (int i = 0 ; i < rf_out; i++)
		{
		    demod = m_phaseDiscri.phaseDiscriminatorDelta(rf[i], msq, fmDev);
		    Real magsq = msq / (1<<30);

			m_movingAverage.feed(magsq);
            m_magsqSum += magsq;

            if (magsq > m_magsqPeak)
            {
                m_magsqPeak = magsq;
            }

            m_magsqCount++;

			if(m_movingAverage.average() >= m_squelchLevel)
				m_squelchState = m_running.m_rfBandwidth / 20; // decay rate

			if (m_squelchState > 0)
			{
				m_squelchState--;
				m_squelchOpen = true;
			}
			else
			{
				demod = 0;
                m_squelchOpen = false;
			}

            if (m_running.m_audioMute)
            {
                demod = 0;
            }

            Complex e(demod, 0);

			if(m_interpolator.decimate(&m_interpolatorDistanceRemain, e, &ci))
			{
				quint16 sample = (qint16)(ci.real() * 3276.8f * m_running.m_volume);
				m_sampleBuffer.push_back(Sample(sample, sample));
				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, 1);

					if(res != m_audioBufferFill)
					{
						qDebug("WFMDemod::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, 1);

		if(res != m_audioBufferFill)
		{
			qDebug("WFMDemod::feed: %u/%u tail samples written", res, m_audioBufferFill);
		}

		m_audioBufferFill = 0;
	}

	if(m_sampleSink != NULL)
	{
		m_sampleSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), false);
	}

	m_sampleBuffer.clear();

	m_settingsMutex.unlock();
}

void WFMDemod::start()
{
	m_squelchState = 0;
	m_audioFifo.clear();
	m_phaseDiscri.reset();
}

void WFMDemod::stop()
{
}

bool WFMDemod::handleMessage(const Message& cmd)
{
	if (DownChannelizer::MsgChannelizerNotification::match(cmd))
	{
		DownChannelizer::MsgChannelizerNotification& notif = (DownChannelizer::MsgChannelizerNotification&) cmd;

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

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

		apply();

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

		m_config.m_rfBandwidth = cfg.getRFBandwidth();
		m_config.m_afBandwidth = cfg.getAFBandwidth();
		m_config.m_volume = cfg.getVolume();
		m_config.m_squelch = cfg.getSquelch();
		m_config.m_audioMute = cfg.getAudioMute();

        qDebug() << "WFMDemod::handleMessage: MsgConfigureWFMDemod: m_rfBandwidth: " << m_config.m_rfBandwidth
                << " m_afBandwidth: " << m_config.m_afBandwidth
                << " m_volume: " << m_config.m_volume
                << " m_squelch: " << m_config.m_squelch
                << " m_audioMute: " << m_config.m_audioMute;

		apply();

		return true;
	}
	else
	{
		if (m_sampleSink != 0)
		{
		    return m_sampleSink->handleMessage(cmd);
		}
		else
		{
			return false;
		}
	}
}

void WFMDemod::apply()
{

	if((m_config.m_inputFrequencyOffset != m_running.m_inputFrequencyOffset) ||
		(m_config.m_inputSampleRate != m_running.m_inputSampleRate))
	{
		qDebug() << "WFMDemod::apply: m_nco.setFreq";
		m_nco.setFreq(-m_config.m_inputFrequencyOffset, m_config.m_inputSampleRate);
	}

	if((m_config.m_inputSampleRate != m_running.m_inputSampleRate) ||
	    (m_config.m_audioSampleRate != m_running.m_audioSampleRate) ||
		(m_config.m_afBandwidth != m_running.m_afBandwidth) ||
		(m_config.m_rfBandwidth != m_running.m_rfBandwidth))
	{
		m_settingsMutex.lock();
		qDebug() << "WFMDemod::apply: m_interpolator.create";
		m_interpolator.create(16, m_config.m_inputSampleRate, m_config.m_afBandwidth);
		m_interpolatorDistanceRemain = (Real) m_config.m_inputSampleRate / (Real) m_config.m_audioSampleRate;
		m_interpolatorDistance =  (Real) m_config.m_inputSampleRate / (Real) m_config.m_audioSampleRate;
        qDebug() << "WFMDemod::apply: m_rfFilter->create_filter";
        Real lowCut = -(m_config.m_rfBandwidth / 2.0) / m_config.m_inputSampleRate;
        Real hiCut  = (m_config.m_rfBandwidth / 2.0) / m_config.m_inputSampleRate;
        m_rfFilter->create_filter(lowCut, hiCut);
        m_fmExcursion = m_config.m_rfBandwidth / (Real) m_config.m_inputSampleRate;
        m_phaseDiscri.setFMScaling(1.0f/m_fmExcursion);
        qDebug("WFMDemod::apply: m_fmExcursion: %f", m_fmExcursion);
		m_settingsMutex.unlock();
	}

	if(m_config.m_squelch != m_running.m_squelch)
	{
		qDebug() << "WFMDemod::apply: set m_squelchLevel";
		m_squelchLevel = pow(10.0, m_config.m_squelch / 20.0);
		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_afBandwidth = m_config.m_afBandwidth;
	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;
}