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sdrangel/plugins/channelrx/demodnfm/nfmdemod.cpp

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///////////////////////////////////////////////////////////////////////////////////
// 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 "nfmdemod.h"
#include <QTime>
#include <QDebug>
#include <stdio.h>
#include <complex.h>
#include <dsp/downchannelizer.h>
#include "audio/audiooutput.h"
#include "dsp/pidcontroller.h"
#include "dsp/dspengine.h"
#include "nfmdemodgui.h"
static const double afSqTones[2] = {1000.0, 6000.0}; // {1200.0, 8000.0};
MESSAGE_CLASS_DEFINITION(NFMDemod::MsgConfigureNFMDemod, Message)
NFMDemod::NFMDemod() :
m_ctcssIndex(0),
m_sampleCount(0),
m_squelchCount(0),
m_squelchGate(2400),
m_audioMute(false),
m_squelchOpen(false),
m_afSquelchOpen(false),
m_magsq(0.0f),
m_magsqSum(0.0f),
m_magsqPeak(0.0f),
m_magsqCount(0),
m_movingAverage(40, 0),
m_afSquelch(2, afSqTones),
m_fmExcursion(2400),
m_audioFifo(4, 48000),
m_settingsMutex(QMutex::Recursive)
{
setObjectName("NFMDemod");
m_config.m_inputSampleRate = 96000;
m_config.m_inputFrequencyOffset = 0;
m_config.m_rfBandwidth = 12500;
m_config.m_afBandwidth = 3000;
m_config.m_fmDeviation = 2000;
m_config.m_squelchGate = 5; // 10s of ms at 48000 Hz sample rate. Corresponds to 2400 for AGC attack
m_config.m_deltaSquelch = false;
m_config.m_squelch = -30.0;
m_config.m_volume = 1.0;
m_config.m_ctcssOn = false;
m_config.m_audioMute = false;
m_config.m_audioSampleRate = DSPEngine::instance()->getAudioSampleRate();
apply();
m_audioBuffer.resize(1<<14);
m_audioBufferFill = 0;
m_agcLevel = 1.0;
m_movingAverage.resize(32, 0);
m_ctcssDetector.setCoefficients(3000, 6000.0); // 0.5s / 2 Hz resolution
m_afSquelch.setCoefficients(24, 600, 48000.0, 200, 0); // 0.5ms test period, 300ms average span, 48kS/s SR, 100ms attack, no decay
DSPEngine::instance()->addAudioSink(&m_audioFifo);
}
NFMDemod::~NFMDemod()
{
DSPEngine::instance()->removeAudioSink(&m_audioFifo);
}
void NFMDemod::configure(MessageQueue* messageQueue,
Real rfBandwidth,
Real afBandwidth,
int fmDeviation,
Real volume,
int squelchGate,
bool deltaSquelch,
Real squelch,
bool ctcssOn,
bool audioMute,
bool force)
{
Message* cmd = MsgConfigureNFMDemod::create(rfBandwidth,
afBandwidth,
fmDeviation,
volume,
squelchGate,
deltaSquelch,
squelch,
ctcssOn,
audioMute,
force);
messageQueue->push(cmd);
}
float arctan2(Real y, Real x)
{
Real coeff_1 = M_PI / 4;
Real coeff_2 = 3 * coeff_1;
Real abs_y = fabs(y) + 1e-10; // kludge to prevent 0/0 condition
Real angle;
if( x>= 0) {
Real r = (x - abs_y) / (x + abs_y);
angle = coeff_1 - coeff_1 * r;
} else {
Real r = (x + abs_y) / (abs_y - x);
angle = coeff_2 - coeff_1 * r;
}
if(y < 0)
return(-angle);
else return(angle);
}
Real angleDist(Real a, Real b)
{
Real dist = b - a;
while(dist <= M_PI)
dist += 2 * M_PI;
while(dist >= M_PI)
dist -= 2 * M_PI;
return dist;
}
void NFMDemod::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end, bool firstOfBurst __attribute__((unused)))
{
Complex ci;
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();
{
if (m_interpolator.decimate(&m_interpolatorDistanceRemain, c, &ci))
{
qint16 sample;
//m_AGC.feed(ci);
//double magsqRaw = m_AGC.getMagSq();
double magsqRaw; // = ci.real()*ci.real() + c.imag()*c.imag();
Real deviation;
Real demod = m_phaseDiscri.phaseDiscriminatorDelta(ci, magsqRaw, deviation);
Real magsq = magsqRaw / (1<<30);
m_movingAverage.feed(magsq);
m_magsqSum += magsq;
if (magsq > m_magsqPeak)
{
m_magsqPeak = magsq;
}
m_magsqCount++;
//m_m2Sample = m_m1Sample;
//m_m1Sample = ci;
m_sampleCount++;
// AF processing
if (m_running.m_deltaSquelch)
{
if (m_afSquelch.analyze(demod)) {
m_afSquelchOpen = m_afSquelch.evaluate() ? m_squelchGate + 480 : 0;
}
if (m_afSquelchOpen)
{
if (m_squelchCount < m_squelchGate + 480)
{
m_squelchCount++;
}
}
else
{
if (m_squelchCount > 0)
{
m_squelchCount--;
}
}
}
else
{
if (m_movingAverage.average() < m_squelchLevel)
{
if (m_squelchCount > 0)
{
m_squelchCount--;
}
}
else
{
if (m_squelchCount < m_squelchGate + 480)
{
m_squelchCount++;
}
}
}
// if ( (m_running.m_deltaSquelch && ((deviation > m_squelchLevel) || (deviation < -m_squelchLevel))) ||
// (!m_running.m_deltaSquelch && (m_movingAverage.average() < m_squelchLevel)) )
// {
// if (m_squelchCount > 0)
// {
// m_squelchCount--;
// }
// }
// else
// {
// if (m_squelchCount < m_squelchGate + 480)
// {
// m_squelchCount++;
// }
// }
//squelchOpen = (getMag() > m_squelchLevel);
m_squelchOpen = (m_squelchCount > m_squelchGate);
/*
if (m_afSquelch.analyze(demod))
{
squelchOpen = m_afSquelch.evaluate();
}*/
if ((m_squelchOpen) && !m_running.m_audioMute)
//if (m_AGC.getAverage() > m_squelchLevel)
{
if (m_running.m_ctcssOn)
{
Real ctcss_sample = m_lowpass.filter(demod);
if ((m_sampleCount & 7) == 7) // decimate 48k -> 6k
{
if (m_ctcssDetector.analyze(&ctcss_sample))
{
int maxToneIndex;
if (m_ctcssDetector.getDetectedTone(maxToneIndex))
{
if (maxToneIndex+1 != m_ctcssIndex)
{
m_nfmDemodGUI->setCtcssFreq(m_ctcssDetector.getToneSet()[maxToneIndex]);
m_ctcssIndex = maxToneIndex+1;
}
}
else
{
if (m_ctcssIndex != 0)
{
m_nfmDemodGUI->setCtcssFreq(0);
m_ctcssIndex = 0;
}
}
}
}
}
if (m_running.m_ctcssOn && m_ctcssIndexSelected && (m_ctcssIndexSelected != m_ctcssIndex))
{
sample = 0;
}
else
{
demod = m_bandpass.filter(demod);
Real squelchFactor = smootherstep((Real) (m_squelchCount - m_squelchGate) / 480.0f);
sample = demod * m_running.m_volume * squelchFactor;
}
}
else
{
if (m_ctcssIndex != 0)
{
m_nfmDemodGUI->setCtcssFreq(0);
m_ctcssIndex = 0;
}
sample = 0;
}
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("NFMDemod::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_settingsMutex.unlock();
}
void NFMDemod::start()
{
qDebug() << "NFMDemod::start";
m_audioFifo.clear();
m_phaseDiscri.reset();
apply(true);
}
void NFMDemod::stop()
{
}
bool NFMDemod::handleMessage(const Message& cmd)
{
qDebug() << "NFMDemod::handleMessage";
if (DownChannelizer::MsgChannelizerNotification::match(cmd))
{
DownChannelizer::MsgChannelizerNotification& notif = (DownChannelizer::MsgChannelizerNotification&) cmd;
m_config.m_inputSampleRate = notif.getSampleRate();
m_config.m_inputFrequencyOffset = notif.getFrequencyOffset();
apply();
qDebug() << "NFMDemod::handleMessage: MsgChannelizerNotification: m_inputSampleRate: " << m_config.m_inputSampleRate
<< " m_inputFrequencyOffset: " << m_config.m_inputFrequencyOffset;
return true;
}
else if (MsgConfigureNFMDemod::match(cmd))
{
MsgConfigureNFMDemod& cfg = (MsgConfigureNFMDemod&) cmd;
m_config.m_rfBandwidth = cfg.getRFBandwidth();
m_config.m_afBandwidth = cfg.getAFBandwidth();
m_config.m_fmDeviation = cfg.getFMDeviation();
m_config.m_volume = cfg.getVolume();
m_config.m_squelchGate = cfg.getSquelchGate();
m_config.m_deltaSquelch = cfg.getDeltaSquelch();
m_config.m_squelch = cfg.getSquelch();
m_config.m_ctcssOn = cfg.getCtcssOn();
m_config.m_audioMute = cfg.getAudioMute();
apply(cfg.getForce());
qDebug() << "NFMDemod::handleMessage: MsgConfigureNFMDemod: m_rfBandwidth: " << m_config.m_rfBandwidth
<< " m_afBandwidth: " << m_config.m_afBandwidth
<< " m_fmDeviation: " << m_config.m_fmDeviation
<< " m_volume: " << m_config.m_volume
<< " m_squelchGate: " << m_config.m_squelchGate
<< " m_deltaSquelch: " << m_config.m_deltaSquelch
<< " m_squelch: " << m_squelchLevel
<< " m_ctcssOn: " << m_config.m_ctcssOn
<< " m_audioMute: " << m_config.m_audioMute
<< " force: " << cfg.getForce();
return true;
}
else
{
return false;
}
}
void NFMDemod::apply(bool force)
{
if ((m_config.m_inputFrequencyOffset != m_running.m_inputFrequencyOffset) ||
(m_config.m_inputSampleRate != m_running.m_inputSampleRate) || force)
{
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) || force)
{
m_settingsMutex.lock();
m_interpolator.create(16, m_config.m_inputSampleRate, m_config.m_rfBandwidth / 2.2);
m_interpolatorDistanceRemain = 0;
m_interpolatorDistance = (Real) m_config.m_inputSampleRate / (Real) m_config.m_audioSampleRate;
m_phaseDiscri.setFMScaling((8.0f*m_config.m_rfBandwidth) / (float) m_config.m_fmDeviation); // integrate 4x factor
m_settingsMutex.unlock();
}
if ((m_config.m_fmDeviation != m_running.m_fmDeviation) || force)
{
m_phaseDiscri.setFMScaling((8.0f*m_config.m_rfBandwidth) / (float) m_config.m_fmDeviation); // integrate 4x factor
}
if ((m_config.m_afBandwidth != m_running.m_afBandwidth) ||
(m_config.m_audioSampleRate != m_running.m_audioSampleRate) || force)
{
m_settingsMutex.lock();
m_lowpass.create(301, m_config.m_audioSampleRate, 250.0);
m_bandpass.create(301, m_config.m_audioSampleRate, 300.0, m_config.m_afBandwidth);
m_settingsMutex.unlock();
}
if ((m_config.m_squelchGate != m_running.m_squelchGate) || force)
{
m_squelchGate = 480 * m_config.m_squelchGate; // gate is given in 10s of ms at 48000 Hz audio sample rate
m_squelchCount = 0; // reset squelch open counter
}
if ((m_config.m_squelch != m_running.m_squelch) ||
(m_config.m_deltaSquelch != m_running.m_deltaSquelch) || force)
{
if (m_config.m_deltaSquelch)
{ // input is a value in negative millis
m_squelchLevel = (- m_config.m_squelch) / 1000.0;
m_afSquelch.setThreshold(m_squelchLevel);
m_afSquelch.reset();
}
else
{ // input is a value in centi-Bels
m_squelchLevel = std::pow(10.0, m_config.m_squelch / 100.0);
}
//m_squelchLevel *= m_squelchLevel;
//m_afSquelch.setThreshold(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_fmDeviation = m_config.m_fmDeviation;
m_running.m_squelchGate = m_config.m_squelchGate;
m_running.m_deltaSquelch = m_config.m_deltaSquelch;
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_ctcssOn = m_config.m_ctcssOn;
m_running.m_audioMute = m_config.m_audioMute;
}
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