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sdrangel/plugins/channelrx/demodvor/vordemodsink.cpp

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///////////////////////////////////////////////////////////////////////////////////
// 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/>. //
///////////////////////////////////////////////////////////////////////////////////
#include <QDebug>
#include <complex.h>
#include "audio/audiooutputdevice.h"
#include "dsp/dspengine.h"
#include "util/db.h"
#include "util/stepfunctions.h"
#include "util/morse.h"
#include "util/units.h"
#include "vordemodreport.h"
#include "vordemodsettings.h"
#include "vordemodsink.h"
VORDemodSCSink::VORDemodSCSink() :
m_channelFrequencyOffset(0),
m_channelSampleRate(VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE),
m_audioSampleRate(48000),
m_squelchCount(0),
m_squelchOpen(false),
m_squelchDelayLine(9600),
m_magsqSum(0.0f),
m_magsqPeak(0.0f),
m_magsqCount(0),
m_volumeAGC(0.003),
m_audioFifo(48000),
m_refPrev(0.0f),
m_movingAverageIdent(5000),
m_prevBit(0),
m_bitTime(0),
m_varGoertzel(30, VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE),
m_refGoertzel(30, VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE)
{
m_audioBuffer.resize(1<<14);
m_audioBufferFill = 0;
m_magsq = 0.0;
applySettings(m_settings, true);
applyChannelSettings(m_channelSampleRate, m_channelFrequencyOffset, true);
}
VORDemodSCSink::~VORDemodSCSink()
{
}
void VORDemodSCSink::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end)
{
Complex ci;
for (SampleVector::const_iterator it = begin; it != end; ++it)
{
Complex c(it->real(), it->imag());
c *= m_nco.nextIQ();
if (m_interpolatorDistance < 1.0f) // interpolate
{
while (!m_interpolator.interpolate(&m_interpolatorDistanceRemain, c, &ci))
{
processOneSample(ci);
m_interpolatorDistanceRemain += m_interpolatorDistance;
}
}
else // decimate
{
if (m_interpolator.decimate(&m_interpolatorDistanceRemain, c, &ci))
{
processOneSample(ci);
m_interpolatorDistanceRemain += m_interpolatorDistance;
}
}
}
}
void VORDemodSCSink::processOneAudioSample(Complex &ci)
{
Real re = ci.real() / SDR_RX_SCALEF;
Real im = ci.imag() / SDR_RX_SCALEF;
Real magsq = re*re + im*im;
m_movingAverage(magsq);
m_magsq = m_movingAverage.asDouble();
m_magsqSum += magsq;
if (magsq > m_magsqPeak)
{
m_magsqPeak = magsq;
}
m_magsqCount++;
m_squelchDelayLine.write(magsq);
if (m_magsq < m_squelchLevel)
{
if (m_squelchCount > 0) {
m_squelchCount--;
}
}
else
{
if (m_squelchCount < (unsigned int)m_audioSampleRate / 10) {
m_squelchCount++;
}
}
qint16 sample;
m_squelchOpen = (m_squelchCount >= (unsigned int)m_audioSampleRate / 20);
if (m_squelchOpen && !m_settings.m_audioMute)
{
Real demod;
{
demod = sqrt(m_squelchDelayLine.readBack(m_audioSampleRate/20));
m_volumeAGC.feed(demod);
demod = (demod - m_volumeAGC.getValue()) / m_volumeAGC.getValue();
}
demod = m_bandpass.filter(demod);
Real attack = (m_squelchCount - 0.05f * m_audioSampleRate) / (0.05f * m_audioSampleRate);
sample = demod * StepFunctions::smootherstep(attack) * (m_audioSampleRate/24) * m_settings.m_volume;
}
else
{
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);
if (res != m_audioBufferFill)
{
qDebug("VORDemodSCSink::processOneAudioSample: %u/%u audio samples written", res, m_audioBufferFill);
m_audioFifo.clear();
}
m_audioBufferFill = 0;
}
}
void VORDemodSCSink::processOneSample(Complex &ci)
{
Complex ca;
// Resample as audio
if (m_audioInterpolatorDistance < 1.0f) // interpolate
{
while (!m_audioInterpolator.interpolate(&m_audioInterpolatorDistanceRemain, ci, &ca))
{
processOneAudioSample(ca);
m_audioInterpolatorDistanceRemain += m_audioInterpolatorDistance;
}
}
else // decimate
{
if (m_audioInterpolator.decimate(&m_audioInterpolatorDistanceRemain, ci, &ca))
{
processOneAudioSample(ca);
m_audioInterpolatorDistanceRemain += m_audioInterpolatorDistance;
}
}
Real re = ci.real() / SDR_RX_SCALEF;
Real im = ci.imag() / SDR_RX_SCALEF;
Real magsq = re*re + im*im;
// AM Demod
Real mag = std::sqrt(magsq);
// Calculate phase of 30Hz variable AM signal
double varPhase;
double varMag;
if (m_varGoertzel.size() == VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE - 1)
{
m_varGoertzel.goertzel(mag);
varPhase = Units::radiansToDegrees(m_varGoertzel.phase());
varMag = m_varGoertzel.mag();
m_varGoertzel.reset();
}
else
m_varGoertzel.filter(mag);
Complex magc(mag, 0.0);
// Mix reference sub-carrier down to 0Hz
Complex fm0 = magc;
fm0 *= m_ncoRef.nextIQ();
// Filter other signals
Complex fmfilt = m_lowpassRef.filter(fm0);
// FM demod
Real phi = std::arg(std::conj(m_refPrev) * fmfilt);
m_refPrev = fmfilt;
// Calculate phase of 30Hz reference FM signal
if (m_refGoertzel.size() == VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE - 1)
{
m_refGoertzel.goertzel(phi);
float phaseDeg = Units::radiansToDegrees(m_refGoertzel.phase());
double refMag = m_refGoertzel.mag();
int groupDelay = (301-1)/2;
float filterPhaseShift = 360.0*30.0*groupDelay/VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE;
float shiftedPhase = phaseDeg + filterPhaseShift;
// Calculate difference in phase, which is the radial
float phaseDifference = shiftedPhase - varPhase;
if (phaseDifference < 0.0)
phaseDifference += 360.0;
else if (phaseDifference >= 360.0)
phaseDifference -= 360.0;
// qDebug() << "Ref phase: " << phaseDeg << " var phase " << varPhase;
if (getMessageQueueToChannel())
{
VORDemodReport::MsgReportRadial *msg = VORDemodReport::MsgReportRadial::create(phaseDifference, refMag, varMag);
getMessageQueueToChannel()->push(msg);
}
m_refGoertzel.reset();
}
else
m_refGoertzel.filter(phi);
// Ident demod
// Remove ident sub-carrier offset
Complex c1 = magc;
c1 *= m_ncoIdent.nextIQ();
// Filter other signals
Complex c2 = std::abs(m_lowpassIdent.filter(c1));
// Filter noise with moving average (moving average preserves edges)
m_movingAverageIdent(c2.real());
Real mav = m_movingAverageIdent.asFloat();
// Caclulate noise floor
if (mav > m_identMaxs[m_binCnt])
m_identMaxs[m_binCnt] = mav;
m_binSampleCnt++;
if (m_binSampleCnt >= m_samplesPerDot10wpm/2)
{
// Calc minimum of maximums
m_identNoise = 1.0f;
for (int i = 0; i < m_identBins; i++)
{
m_identNoise = std::min(m_identNoise, m_identMaxs[i]);
}
m_binSampleCnt = 0;
m_binCnt++;
if (m_binCnt == m_identBins)
m_binCnt = 0;
m_identMaxs[m_binCnt] = 0.0f;
// Prevent divide by zero
if (m_identNoise == 0.0f)
m_identNoise = 1e-20f;
}
// CW demod
int bit = (mav / m_identNoise) >= m_settings.m_identThreshold;
if ((m_prevBit == 0) && (bit == 1))
{
if (m_bitTime > 7*m_samplesPerDot10wpm)
{
if (m_ident != "")
{
qDebug() << "VORDemodSCSink::processOneSample:" << m_ident << " " << Morse::toString(m_ident);
if (getMessageQueueToChannel())
{
VORDemodReport::MsgReportIdent *msg = VORDemodReport::MsgReportIdent::create(m_ident);
getMessageQueueToChannel()->push(msg);
}
m_ident = "";
}
}
else if (m_bitTime > 2.5*m_samplesPerDot10wpm)
{
m_ident.append(" ");
}
m_bitTime = 0;
}
else if (bit == 1)
{
m_bitTime++;
}
else if ((m_prevBit == 1) && (bit == 0))
{
if (m_bitTime > 2*m_samplesPerDot10wpm)
{
m_ident.append("-");
}
else if (m_bitTime > 0.2*m_samplesPerDot10wpm)
{
m_ident.append(".");
}
m_bitTime = 0;
}
else
{
m_bitTime++;
if (m_bitTime > 10*m_samplesPerDot7wpm)
{
m_ident = m_ident.simplified();
if (m_ident != "")
{
qDebug() << "VORDemodSCSink::processOneSample:" << m_ident << " " << Morse::toString(m_ident);
if (getMessageQueueToChannel())
{
VORDemodReport::MsgReportIdent *msg = VORDemodReport::MsgReportIdent::create(m_ident);
getMessageQueueToChannel()->push(msg);
}
m_ident = "";
}
m_bitTime = 0;
}
}
m_prevBit = bit;
}
void VORDemodSCSink::applyChannelSettings(int channelSampleRate, int channelFrequencyOffset, bool force)
{
qDebug() << "VORDemodSCSink::applyChannelSettings:"
<< " channelSampleRate: " << channelSampleRate
<< " channelFrequencyOffset: " << channelFrequencyOffset;
if ((m_channelFrequencyOffset != channelFrequencyOffset) ||
(m_channelSampleRate != channelSampleRate) || force)
{
m_nco.setFreq(-channelFrequencyOffset, channelSampleRate);
}
if ((m_channelSampleRate != channelSampleRate) || force)
{
m_interpolator.create(16, channelSampleRate, VORDemodSettings::VORDEMOD_CHANNEL_BANDWIDTH);
m_interpolatorDistanceRemain = 0;
m_interpolatorDistance = (Real) channelSampleRate / (Real) VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE;
m_samplesPerDot7wpm = VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE*60/(50*7);
m_samplesPerDot10wpm = VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE*60/(50*10);
m_ncoIdent.setFreq(-1020, VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE); // +-50Hz source offset allowed
m_ncoRef.setFreq(-9960, VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE);
m_lowpassIdent.create(301, VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE, 100.0f);
m_lowpassRef.create(301, VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE, 600.0f); // Max deviation is 480Hz
m_movingAverageIdent.resize(m_samplesPerDot10wpm/5); // Needs to be short enough for noise floor calculation
m_binSampleCnt = 0;
m_binCnt = 0;
m_identNoise = 0.0001f;
for (int i = 0; i < m_identBins; i++)
{
m_identMaxs[i] = 0.0f;
}
}
m_channelSampleRate = channelSampleRate;
m_channelFrequencyOffset = channelFrequencyOffset;
}
void VORDemodSCSink::applySettings(const VORDemodSettings& settings, bool force)
{
qDebug() << "VORDemodSCSink::applySettings:"
<< " m_volume: " << settings.m_volume
<< " m_squelch: " << settings.m_squelch
<< " m_audioMute: " << settings.m_audioMute
<< " m_audioDeviceName: " << settings.m_audioDeviceName
<< " force: " << force;
if ((m_settings.m_squelch != settings.m_squelch) || force) {
m_squelchLevel = CalcDb::powerFromdB(settings.m_squelch);
}
if (m_settings.m_navId != settings.m_navId)
{
// Reset state when navId changes, so we don't report old ident for new navId
m_binSampleCnt = 0;
m_binCnt = 0;
m_identNoise = 0.0001f;
for (int i = 0; i < m_identBins; i++)
{
m_identMaxs[i] = 0.0f;
}
m_ident = "";
m_refGoertzel.reset();
m_varGoertzel.reset();
}
m_settings = settings;
}
void VORDemodSCSink::applyAudioSampleRate(int sampleRate)
{
if (sampleRate < 0)
{
qWarning("VORDemodSCSink::applyAudioSampleRate: invalid sample rate: %d", sampleRate);
return;
}
qDebug("VORDemodSCSink::applyAudioSampleRate: sampleRate: %d m_channelSampleRate: %d", sampleRate, m_channelSampleRate);
// (ICAO Annex 10 3.3.6.3) - Optional voice audio is 300Hz to 3kHz
m_audioInterpolator.create(16, VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE, 3000.0f);
m_audioInterpolatorDistanceRemain = 0;
m_audioInterpolatorDistance = (Real) VORDemodSettings::VORDEMOD_CHANNEL_SAMPLE_RATE / (Real) sampleRate;
m_bandpass.create(301, sampleRate, 300.0f, 3000.0f);
m_audioFifo.setSize(sampleRate);
m_squelchDelayLine.resize(sampleRate/5);
m_volumeAGC.resizeNew(sampleRate/10, 0.003f);
m_audioSampleRate = sampleRate;
}
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