/////////////////////////////////////////////////////////////////////////////////// // 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 . // /////////////////////////////////////////////////////////////////////////////////// #include #include #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; }