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429 lines
14 KiB
C++
429 lines
14 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2019 Edouard Griffiths, F4EXB //
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// Copyright (C) 2020 Jon Beniston, M7RCE //
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// //
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// This program is free software; you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation as version 3 of the License, or //
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// (at your option) any later version. //
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// //
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// This program is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License V3 for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with this program. If not, see <http://www.gnu.org/licenses/>. //
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///////////////////////////////////////////////////////////////////////////////////
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#include <QDebug>
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#include <complex.h>
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#include "audio/audiooutputdevice.h"
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#include "dsp/dspengine.h"
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#include "util/db.h"
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#include "util/stepfunctions.h"
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#include "util/morse.h"
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#include "util/units.h"
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#include "vordemodscreport.h"
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#include "vordemodscsettings.h"
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#include "vordemodscsink.h"
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VORDemodSCSink::VORDemodSCSink() :
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m_channelFrequencyOffset(0),
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m_channelSampleRate(VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE),
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m_audioSampleRate(48000),
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m_squelchCount(0),
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m_squelchOpen(false),
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m_squelchDelayLine(9600),
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m_magsqSum(0.0f),
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m_magsqPeak(0.0f),
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m_magsqCount(0),
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m_volumeAGC(0.003),
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m_audioFifo(48000),
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m_refPrev(0.0f),
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m_movingAverageIdent(5000),
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m_prevBit(0),
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m_bitTime(0),
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m_varGoertzel(30, VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE),
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m_refGoertzel(30, VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE)
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{
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m_audioBuffer.resize(1<<14);
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m_audioBufferFill = 0;
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m_magsq = 0.0;
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applySettings(m_settings, true);
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applyChannelSettings(m_channelSampleRate, m_channelFrequencyOffset, true);
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}
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VORDemodSCSink::~VORDemodSCSink()
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{
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}
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void VORDemodSCSink::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end)
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{
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Complex ci;
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for (SampleVector::const_iterator it = begin; it != end; ++it)
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{
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Complex c(it->real(), it->imag());
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c *= m_nco.nextIQ();
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if (m_interpolatorDistance < 1.0f) // interpolate
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{
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while (!m_interpolator.interpolate(&m_interpolatorDistanceRemain, c, &ci))
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{
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processOneSample(ci);
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m_interpolatorDistanceRemain += m_interpolatorDistance;
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}
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}
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else // decimate
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{
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if (m_interpolator.decimate(&m_interpolatorDistanceRemain, c, &ci))
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{
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processOneSample(ci);
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m_interpolatorDistanceRemain += m_interpolatorDistance;
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}
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}
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}
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}
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void VORDemodSCSink::processOneAudioSample(Complex &ci)
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{
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Real re = ci.real() / SDR_RX_SCALEF;
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Real im = ci.imag() / SDR_RX_SCALEF;
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Real magsq = re*re + im*im;
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m_movingAverage(magsq);
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m_magsq = m_movingAverage.asDouble();
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m_magsqSum += magsq;
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if (magsq > m_magsqPeak)
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{
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m_magsqPeak = magsq;
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}
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m_magsqCount++;
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m_squelchDelayLine.write(magsq);
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if (m_magsq < m_squelchLevel)
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{
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if (m_squelchCount > 0) {
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m_squelchCount--;
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}
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}
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else
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{
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if (m_squelchCount < (unsigned int)m_audioSampleRate / 10) {
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m_squelchCount++;
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}
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}
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qint16 sample;
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m_squelchOpen = (m_squelchCount >= (unsigned int)m_audioSampleRate / 20);
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if (m_squelchOpen && !m_settings.m_audioMute)
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{
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Real demod;
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{
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demod = sqrt(m_squelchDelayLine.readBack(m_audioSampleRate/20));
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m_volumeAGC.feed(demod);
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demod = (demod - m_volumeAGC.getValue()) / m_volumeAGC.getValue();
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}
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demod = m_bandpass.filter(demod);
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Real attack = (m_squelchCount - 0.05f * m_audioSampleRate) / (0.05f * m_audioSampleRate);
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sample = demod * StepFunctions::smootherstep(attack) * (m_audioSampleRate/24) * m_settings.m_volume;
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}
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else
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{
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sample = 0;
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}
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m_audioBuffer[m_audioBufferFill].l = sample;
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m_audioBuffer[m_audioBufferFill].r = sample;
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++m_audioBufferFill;
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if (m_audioBufferFill >= m_audioBuffer.size())
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{
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uint res = m_audioFifo.write((const quint8*)&m_audioBuffer[0], m_audioBufferFill);
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if (res != m_audioBufferFill)
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{
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qDebug("VORDemodSCSink::processOneAudioSample: %u/%u audio samples written", res, m_audioBufferFill);
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m_audioFifo.clear();
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}
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m_audioBufferFill = 0;
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}
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}
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void VORDemodSCSink::processOneSample(Complex &ci)
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{
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Complex ca;
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// Resample as audio
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if (m_audioInterpolatorDistance < 1.0f) // interpolate
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{
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while (!m_audioInterpolator.interpolate(&m_audioInterpolatorDistanceRemain, ci, &ca))
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{
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processOneAudioSample(ca);
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m_audioInterpolatorDistanceRemain += m_audioInterpolatorDistance;
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}
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}
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else // decimate
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{
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if (m_audioInterpolator.decimate(&m_audioInterpolatorDistanceRemain, ci, &ca))
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{
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processOneAudioSample(ca);
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m_audioInterpolatorDistanceRemain += m_audioInterpolatorDistance;
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}
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}
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Real re = ci.real() / SDR_RX_SCALEF;
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Real im = ci.imag() / SDR_RX_SCALEF;
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Real magsq = re*re + im*im;
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// AM Demod
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Real mag = std::sqrt(magsq);
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// Calculate phase of 30Hz variable AM signal
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double varPhase;
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double varMag;
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if (m_varGoertzel.size() == VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE - 1)
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{
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m_varGoertzel.goertzel(mag);
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varPhase = Units::radiansToDegrees(m_varGoertzel.phase());
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varMag = m_varGoertzel.mag();
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m_varGoertzel.reset();
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}
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else
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m_varGoertzel.filter(mag);
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Complex magc(mag, 0.0);
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// Mix reference sub-carrier down to 0Hz
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Complex fm0 = magc;
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fm0 *= m_ncoRef.nextIQ();
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// Filter other signals
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Complex fmfilt = m_lowpassRef.filter(fm0);
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// FM demod
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Real phi = std::arg(std::conj(m_refPrev) * fmfilt);
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m_refPrev = fmfilt;
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// Calculate phase of 30Hz reference FM signal
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if (m_refGoertzel.size() == VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE - 1)
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{
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m_refGoertzel.goertzel(phi);
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float phaseDeg = Units::radiansToDegrees(m_refGoertzel.phase());
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double refMag = m_refGoertzel.mag();
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int groupDelay = (301-1)/2;
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float filterPhaseShift = 360.0*30.0*groupDelay/VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE;
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float shiftedPhase = phaseDeg + filterPhaseShift;
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// Calculate difference in phase, which is the radial
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float phaseDifference = shiftedPhase - varPhase;
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if (phaseDifference < 0.0)
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phaseDifference += 360.0;
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else if (phaseDifference >= 360.0)
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phaseDifference -= 360.0;
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// qDebug() << "Ref phase: " << phaseDeg << " var phase " << varPhase;
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if (getMessageQueueToChannel())
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{
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VORDemodSCReport::MsgReportRadial *msg = VORDemodSCReport::MsgReportRadial::create(phaseDifference, refMag, varMag);
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getMessageQueueToChannel()->push(msg);
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}
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m_refGoertzel.reset();
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}
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else
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m_refGoertzel.filter(phi);
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// Ident demod
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// Remove ident sub-carrier offset
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Complex c1 = magc;
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c1 *= m_ncoIdent.nextIQ();
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// Filter other signals
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Complex c2 = std::abs(m_lowpassIdent.filter(c1));
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// Filter noise with moving average (moving average preserves edges)
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m_movingAverageIdent(c2.real());
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Real mav = m_movingAverageIdent.asFloat();
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// Caclulate noise floor
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if (mav > m_identMaxs[m_binCnt])
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m_identMaxs[m_binCnt] = mav;
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m_binSampleCnt++;
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if (m_binSampleCnt >= m_samplesPerDot10wpm/2)
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{
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// Calc minimum of maximums
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m_identNoise = 1.0f;
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for (int i = 0; i < m_identBins; i++)
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{
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m_identNoise = std::min(m_identNoise, m_identMaxs[i]);
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}
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m_binSampleCnt = 0;
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m_binCnt++;
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if (m_binCnt == m_identBins)
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m_binCnt = 0;
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m_identMaxs[m_binCnt] = 0.0f;
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// Prevent divide by zero
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if (m_identNoise == 0.0f)
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m_identNoise = 1e-20f;
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}
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// CW demod
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int bit = (mav / m_identNoise) >= m_settings.m_identThreshold;
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if ((m_prevBit == 0) && (bit == 1))
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{
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if (m_bitTime > 7*m_samplesPerDot10wpm)
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{
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if (m_ident != "")
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{
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qDebug() << "VORDemodSCSink::processOneSample:" << m_ident << " " << Morse::toString(m_ident);
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if (getMessageQueueToChannel())
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{
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VORDemodSCReport::MsgReportIdent *msg = VORDemodSCReport::MsgReportIdent::create(m_ident);
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getMessageQueueToChannel()->push(msg);
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}
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m_ident = "";
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}
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}
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else if (m_bitTime > 2.5*m_samplesPerDot10wpm)
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{
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m_ident.append(" ");
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}
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m_bitTime = 0;
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}
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else if (bit == 1)
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{
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m_bitTime++;
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}
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else if ((m_prevBit == 1) && (bit == 0))
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{
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if (m_bitTime > 2*m_samplesPerDot10wpm)
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{
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m_ident.append("-");
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}
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else if (m_bitTime > 0.2*m_samplesPerDot10wpm)
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{
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m_ident.append(".");
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}
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m_bitTime = 0;
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}
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else
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{
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m_bitTime++;
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if (m_bitTime > 10*m_samplesPerDot7wpm)
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{
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m_ident = m_ident.simplified();
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if (m_ident != "")
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{
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qDebug() << "VORDemodSCSink::processOneSample:" << m_ident << " " << Morse::toString(m_ident);
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if (getMessageQueueToChannel())
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{
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VORDemodSCReport::MsgReportIdent *msg = VORDemodSCReport::MsgReportIdent::create(m_ident);
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getMessageQueueToChannel()->push(msg);
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}
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m_ident = "";
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}
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m_bitTime = 0;
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}
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}
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m_prevBit = bit;
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}
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void VORDemodSCSink::applyChannelSettings(int channelSampleRate, int channelFrequencyOffset, bool force)
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{
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qDebug() << "VORDemodSCSink::applyChannelSettings:"
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<< " channelSampleRate: " << channelSampleRate
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<< " channelFrequencyOffset: " << channelFrequencyOffset;
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if ((m_channelFrequencyOffset != channelFrequencyOffset) ||
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(m_channelSampleRate != channelSampleRate) || force)
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{
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m_nco.setFreq(-channelFrequencyOffset, channelSampleRate);
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}
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if ((m_channelSampleRate != channelSampleRate) || force)
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{
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m_interpolator.create(16, channelSampleRate, VORDemodSCSettings::VORDEMOD_CHANNEL_BANDWIDTH);
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m_interpolatorDistanceRemain = 0;
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m_interpolatorDistance = (Real) channelSampleRate / (Real) VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE;
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m_samplesPerDot7wpm = VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE*60/(50*7);
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m_samplesPerDot10wpm = VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE*60/(50*10);
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m_ncoIdent.setFreq(-1020, VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE); // +-50Hz source offset allowed
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m_ncoRef.setFreq(-9960, VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE);
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m_lowpassIdent.create(301, VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE, 100.0f);
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m_lowpassRef.create(301, VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE, 600.0f); // Max deviation is 480Hz
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m_movingAverageIdent.resize(m_samplesPerDot10wpm/5); // Needs to be short enough for noise floor calculation
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m_binSampleCnt = 0;
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m_binCnt = 0;
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m_identNoise = 0.0001f;
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for (int i = 0; i < m_identBins; i++)
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{
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m_identMaxs[i] = 0.0f;
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}
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}
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m_channelSampleRate = channelSampleRate;
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m_channelFrequencyOffset = channelFrequencyOffset;
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}
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void VORDemodSCSink::applySettings(const VORDemodSCSettings& settings, bool force)
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{
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qDebug() << "VORDemodSCSink::applySettings:"
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<< " m_volume: " << settings.m_volume
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<< " m_squelch: " << settings.m_squelch
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<< " m_audioMute: " << settings.m_audioMute
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<< " m_audioDeviceName: " << settings.m_audioDeviceName
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<< " force: " << force;
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if ((m_settings.m_squelch != settings.m_squelch) || force) {
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m_squelchLevel = CalcDb::powerFromdB(settings.m_squelch);
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}
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m_settings = settings;
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}
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void VORDemodSCSink::applyAudioSampleRate(int sampleRate)
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{
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if (sampleRate < 0)
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{
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qWarning("VORDemodSCSink::applyAudioSampleRate: invalid sample rate: %d", sampleRate);
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return;
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}
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qDebug("VORDemodSCSink::applyAudioSampleRate: sampleRate: %d m_channelSampleRate: %d", sampleRate, m_channelSampleRate);
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// (ICAO Annex 10 3.3.6.3) - Optional voice audio is 300Hz to 3kHz
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m_audioInterpolator.create(16, VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE, 3000.0f);
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m_audioInterpolatorDistanceRemain = 0;
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m_audioInterpolatorDistance = (Real) VORDemodSCSettings::VORDEMOD_CHANNEL_SAMPLE_RATE / (Real) sampleRate;
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m_bandpass.create(301, sampleRate, 300.0f, 3000.0f);
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m_audioFifo.setSize(sampleRate);
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m_squelchDelayLine.resize(sampleRate/5);
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m_volumeAGC.resizeNew(sampleRate/10, 0.003f);
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m_audioSampleRate = sampleRate;
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}
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