mirror of
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571 lines
20 KiB
C++
571 lines
20 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 <cctype>
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#include <QDebug>
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#include "dsp/basebandsamplesink.h"
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#include "packetmodsource.h"
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#include "util/crc.h"
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PacketModSource::PacketModSource() :
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m_channelSampleRate(48000),
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m_spectrumRate(0),
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m_preemphasisFilter(48000, FMPREEMPHASIS_TAU_US),
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m_channelFrequencyOffset(0),
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m_magsq(0.0),
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m_audioPhase(0.0f),
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m_fmPhase(0.0),
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m_levelCalcCount(0),
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m_peakLevel(0.0f),
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m_levelSum(0.0f),
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m_bitCount(0),
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m_byteIdx(0),
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m_bitIdx(0),
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m_last5Bits(0),
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m_state(idle),
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m_scrambler(0x10800, 0x0)
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{
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m_lowpass.create(301, m_channelSampleRate, 22000.0 / 2.0);
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qDebug() << "PacketModSource::PacketModSource creating BPF : " << m_channelSampleRate;
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m_bandpass.create(301, m_channelSampleRate, 800.0, 2600.0);
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m_pulseShape.create(0.5, 6, m_channelSampleRate/9600);
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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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PacketModSource::~PacketModSource()
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{
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}
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void PacketModSource::pull(SampleVector::iterator begin, unsigned int nbSamples)
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{
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std::for_each(
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begin,
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begin + nbSamples,
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[this](Sample& s) {
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pullOne(s);
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}
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);
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}
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void PacketModSource::pullOne(Sample& sample)
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{
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if (m_settings.m_channelMute)
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{
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sample.m_real = 0.0f;
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sample.m_imag = 0.0f;
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return;
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}
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// Calculate next sample
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modulateSample();
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// Shift to carrier frequency
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Complex ci = m_modSample;
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ci *= m_carrierNco.nextIQ();
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// Calculate power
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double magsq = ci.real() * ci.real() + ci.imag() * ci.imag();
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m_movingAverage(magsq);
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m_magsq = m_movingAverage.asDouble();
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// Convert from float to fixed point
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sample.m_real = (FixReal) (ci.real() * SDR_TX_SCALEF);
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sample.m_imag = (FixReal) (ci.imag() * SDR_TX_SCALEF);
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}
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void PacketModSource::prefetch(unsigned int nbSamples)
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{
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}
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void PacketModSource::sampleToSpectrum(Real sample)
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{
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if (m_spectrumSink)
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{
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Complex out;
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Complex in;
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in.real(sample);
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in.imag(0.0f);
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if (m_interpolator.decimate(&m_interpolatorDistanceRemain, in, &out))
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{
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sample = std::real(out);
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m_sampleBuffer.push_back(Sample(sample * 0.891235351562f * SDR_TX_SCALEF, 0.0f));
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m_spectrumSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), true);
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m_sampleBuffer.clear();
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m_interpolatorDistanceRemain += m_interpolatorDistance;
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}
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}
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}
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void PacketModSource::modulateSample()
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{
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Real audioMod;
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Real linearRampGain;
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Real emphasis;
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if ((m_state == idle) || (m_state == wait))
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{
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audioMod = 0.0f;
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m_modSample.real(audioMod);
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m_modSample.imag(0);
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calculateLevel(audioMod);
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sampleToSpectrum(audioMod);
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if (m_state == wait)
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{
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m_waitCounter--;
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if (m_waitCounter == 0)
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initTX();
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}
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}
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else
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{
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if (m_sampleIdx == 0)
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{
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if (bitsValid())
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{
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// NRZI encoding - encode 0 as change of freq, 1 no change
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if (getBit() == 0)
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m_nrziBit = m_nrziBit == 1 ? 0 : 1;
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// Scramble to ensure lots of transitions
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if (m_settings.m_scramble)
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m_scrambledBit = m_scrambler.scramble(m_nrziBit);
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else
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m_scrambledBit = m_nrziBit;
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}
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// Should we start ramping down power?
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if ((m_bitCount < m_settings.m_rampDownBits) || ((m_bitCount == 0) && !m_settings.m_rampDownBits))
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{
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m_state = ramp_down;
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if (m_settings.m_rampDownBits > 0)
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m_powRamp = -m_settings.m_rampRange/(m_settings.m_rampDownBits * (Real)m_samplesPerSymbol);
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}
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}
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m_sampleIdx++;
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if (m_sampleIdx >= m_samplesPerSymbol)
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m_sampleIdx = 0;
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if (!m_settings.m_bbNoise)
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{
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if (m_settings.m_modulation == PacketModSettings::AFSK)
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{
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// Bell 202 AFSK
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audioMod = sin(m_audioPhase);
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if ((m_state == tx) || m_settings.m_modulateWhileRamping)
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m_audioPhase += (M_PI * 2.0f * (m_scrambledBit ? m_settings.m_markFrequency : m_settings.m_spaceFrequency)) / (m_channelSampleRate);
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if (m_audioPhase > M_PI)
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m_audioPhase -= (2.0f * M_PI);
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}
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else
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{
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// FSK
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if (m_settings.m_pulseShaping)
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{
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if ((m_sampleIdx == 1) && (m_state != ramp_down))
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audioMod = m_pulseShape.filter(m_scrambledBit ? 1.0f : -1.0f);
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else
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audioMod = m_pulseShape.filter(0.0f);
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}
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else
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audioMod = m_scrambledBit ? 1.0f : -1.0f;
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}
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}
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else
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audioMod = (Real)rand()/((Real)RAND_MAX)-0.5; // Noise to test filter frequency response
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// Baseband bandpass filter
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if (m_settings.m_bpf)
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audioMod = m_bandpass.filter(audioMod);
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// Preemphasis filter
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if (m_settings.m_preEmphasis)
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audioMod = m_preemphasisFilter.filter(audioMod);
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if (m_audioFile.is_open())
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m_audioFile << audioMod << "\n";
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// Display baseband audio in spectrum analyser
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sampleToSpectrum(audioMod);
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// FM
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m_fmPhase += m_phaseSensitivity * audioMod;
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// Keep phase in range -pi,pi
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if (m_fmPhase > M_PI)
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m_fmPhase -= 2.0f * M_PI;
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else if (m_fmPhase < -M_PI)
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m_fmPhase += 2.0f * M_PI;
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linearRampGain = powf(10.0f, m_pow/20.0f);
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if (!m_settings.m_rfNoise)
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{
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m_modSample.real(m_linearGain * linearRampGain * cos(m_fmPhase));
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m_modSample.imag(m_linearGain * linearRampGain * sin(m_fmPhase));
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}
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else
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{
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// Noise to test filter frequency response
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m_modSample.real(m_linearGain * ((Real)rand()/((Real)RAND_MAX)-0.5f));
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m_modSample.imag(m_linearGain * ((Real)rand()/((Real)RAND_MAX)-0.5f));
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}
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// Apply low pass filter to limit RF BW
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m_modSample = m_lowpass.filter(m_modSample);
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// Ramp up/down power at start/end of packet
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if ((m_state == ramp_up) || (m_state == ramp_down))
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{
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m_pow += m_powRamp;
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if ((m_state == ramp_up) && (m_pow >= 0.0f))
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{
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// Finished ramp up, transmit at full gain
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m_state = tx;
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m_pow = 0.0f;
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}
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else if ((m_state == ramp_down) && ( (m_settings.m_rampRange == 0)
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|| (m_settings.m_rampDownBits == 0)
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|| (m_pow <= -(Real)m_settings.m_rampRange)
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))
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{
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m_state = idle;
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// Do we need to retransmit the packet?
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if (m_settings.m_repeat)
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{
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if (m_packetRepeatCount > 0)
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m_packetRepeatCount--;
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if ((m_packetRepeatCount == PacketModSettings::infinitePackets) || (m_packetRepeatCount > 0))
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{
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if (m_settings.m_repeatDelay > 0.0f)
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{
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// Wait before retransmitting
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m_state = wait;
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m_waitCounter = m_settings.m_repeatDelay * m_channelSampleRate;
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}
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else
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{
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// Retransmit immediately
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initTX();
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}
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}
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}
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}
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}
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Real s = std::real(m_modSample);
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calculateLevel(s);
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}
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}
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void PacketModSource::calculateLevel(Real& sample)
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{
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if (m_levelCalcCount < m_levelNbSamples)
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{
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m_peakLevel = std::max(std::fabs(m_peakLevel), sample);
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m_levelSum += sample * sample;
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m_levelCalcCount++;
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}
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else
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{
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m_rmsLevel = sqrt(m_levelSum / m_levelNbSamples);
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m_peakLevelOut = m_peakLevel;
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m_peakLevel = 0.0f;
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m_levelSum = 0.0f;
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m_levelCalcCount = 0;
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}
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}
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void PacketModSource::applySettings(const PacketModSettings& settings, bool force)
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{
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// Only recreate filters if settings have changed
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if ((settings.m_lpfTaps != m_settings.m_lpfTaps) || (settings.m_rfBandwidth != m_settings.m_rfBandwidth) || force)
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{
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qDebug() << "PacketModSource::applySettings: Creating new lpf with taps " << settings.m_lpfTaps << " rfBW " << settings.m_rfBandwidth;
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m_lowpass.create(settings.m_lpfTaps, m_channelSampleRate, settings.m_rfBandwidth / 2.0);
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}
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if ((settings.m_preEmphasisTau != m_settings.m_preEmphasisTau) || (settings.m_preEmphasisHighFreq != m_settings.m_preEmphasisHighFreq) || force)
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{
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qDebug() << "PacketModSource::applySettings: Creating new preemphasis filter with tau " << settings.m_preEmphasisTau << " highFreq " << settings.m_preEmphasisHighFreq << " sampleRate " << m_channelSampleRate;
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m_preemphasisFilter.configure(m_channelSampleRate, settings.m_preEmphasisTau, settings.m_preEmphasisHighFreq);
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}
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if ((settings.m_bpfLowCutoff != m_settings.m_bpfLowCutoff) || (settings.m_bpfHighCutoff != m_settings.m_bpfHighCutoff)
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|| (settings.m_bpfTaps != m_settings.m_bpfTaps)|| force)
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{
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qDebug() << "PacketModSource::applySettings: Recreating bandpass filter: "
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<< " m_bpfTaps: " << settings.m_bpfTaps
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<< " m_channelSampleRate:" << m_channelSampleRate
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<< " m_bpfLowCutoff: " << settings.m_bpfLowCutoff
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<< " m_bpfHighCutoff: " << settings.m_bpfHighCutoff;
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m_bandpass.create(settings.m_bpfTaps, m_channelSampleRate, settings.m_bpfLowCutoff, settings.m_bpfHighCutoff);
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}
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if ((settings.m_beta != m_settings.m_beta) || (settings.m_symbolSpan != m_settings.m_symbolSpan) || (settings.m_baud != m_settings.m_baud) || force)
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{
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qDebug() << "PacketModSource::applySettings: Recreating pulse shaping filter: "
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<< " beta: " << settings.m_beta
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<< " symbolSpan: " << settings.m_symbolSpan
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<< " channelSampleRate:" << m_channelSampleRate
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<< " baud:" << settings.m_baud;
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m_pulseShape.create(settings.m_beta, m_settings.m_symbolSpan, m_channelSampleRate/settings.m_baud);
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}
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if ((settings.m_polynomial != m_settings.m_polynomial) || force)
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m_scrambler.setPolynomial(settings.m_polynomial);
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if ((settings.m_spectrumRate != m_settings.m_spectrumRate) || force)
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{
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m_interpolatorDistanceRemain = 0;
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m_interpolatorConsumed = false;
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m_interpolatorDistance = (Real) m_channelSampleRate / (Real) settings.m_spectrumRate;
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m_interpolator.create(48, settings.m_spectrumRate, settings.m_spectrumRate / 2.2, 3.0);
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}
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m_settings = settings;
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// Precalculate FM sensensity and linear gain to save doing it in the loop
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m_phaseSensitivity = 2.0f * M_PI * m_settings.m_fmDeviation / (double)m_channelSampleRate;
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m_linearGain = powf(10.0f, m_settings.m_gain/20.0f);
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}
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void PacketModSource::applyChannelSettings(int channelSampleRate, int channelFrequencyOffset, bool force)
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{
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qDebug() << "PacketModSource::applyChannelSettings:"
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<< " channelSampleRate: " << channelSampleRate
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<< " channelFrequencyOffset: " << channelFrequencyOffset
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<< " rfBandwidth: " << m_settings.m_rfBandwidth
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<< " spectrumRate: " << m_settings.m_spectrumRate;
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if ((channelFrequencyOffset != m_channelFrequencyOffset)
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|| (channelSampleRate != m_channelSampleRate) || force)
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{
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m_carrierNco.setFreq(channelFrequencyOffset, channelSampleRate);
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}
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if ((m_channelSampleRate != channelSampleRate) || force)
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{
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qDebug() << "PacketModSource::applyChannelSettings: Recreating filters";
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m_lowpass.create(m_settings.m_lpfTaps, channelSampleRate, m_settings.m_rfBandwidth / 2.0);
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qDebug() << "PacketModSource::applyChannelSettings: Recreating bandpass filter: "
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<< " bpfTaps: " << m_settings.m_bpfTaps
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<< " channelSampleRate:" << channelSampleRate
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<< " bpfLowCutoff: " << m_settings.m_bpfLowCutoff
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<< " bpfHighCutoff: " << m_settings.m_bpfHighCutoff;
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m_bandpass.create(m_settings.m_bpfTaps, channelSampleRate, m_settings.m_bpfLowCutoff, m_settings.m_bpfHighCutoff);
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m_preemphasisFilter.configure(channelSampleRate, m_settings.m_preEmphasisTau);
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qDebug() << "PacketModSource::applyChannelSettings: Recreating pulse shaping filter: "
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<< " beta: " << m_settings.m_beta
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<< " symbolSpan: " << m_settings.m_symbolSpan
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<< " channelSampleRate:" << m_channelSampleRate
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<< " baud:" << m_settings.m_baud;
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m_pulseShape.create(m_settings.m_beta, m_settings.m_symbolSpan, channelSampleRate/m_settings.m_baud);
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}
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if ((m_channelSampleRate != channelSampleRate) || (m_spectrumRate != m_settings.m_spectrumRate) || force)
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{
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m_interpolatorDistanceRemain = 0;
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m_interpolatorConsumed = false;
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m_interpolatorDistance = (Real) channelSampleRate / (Real) m_settings.m_spectrumRate;
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m_interpolator.create(48, m_settings.m_spectrumRate, m_settings.m_spectrumRate / 2.2, 3.0);
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}
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m_channelSampleRate = channelSampleRate;
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m_channelFrequencyOffset = channelFrequencyOffset;
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m_spectrumRate = m_settings.m_spectrumRate;
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m_samplesPerSymbol = m_channelSampleRate / m_settings.m_baud;
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qDebug() << "m_samplesPerSymbol: " << m_samplesPerSymbol << " (" << m_channelSampleRate << "/" << m_settings.m_baud << ")";
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// Precalculate FM sensensity to save doing it in the loop
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m_phaseSensitivity = 2.0f * M_PI * m_settings.m_fmDeviation / (double)m_channelSampleRate;
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}
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static uint8_t *ax25_address(uint8_t *p, QString address, uint8_t crrl)
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{
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int len;
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int i;
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QByteArray b;
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int ssid;
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len = address.length();
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b = address.toUtf8();
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ssid = 0;
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for (i = 0; i < 6; i++)
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{
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if ((i < len) && (ssid == 0))
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{
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if (b[i] == '-')
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{
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if (len > i + 1)
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{
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ssid = b[i+1] - '0';
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if ((len > i + 2) && isdigit(b[i+2])) {
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ssid = (ssid*10) + (b[i+1] - '0');
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}
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if (ssid >= 16)
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qDebug() << "ax25_address: SSID greater than 15 not supported";
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}
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else
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qDebug() << "ax25_address: SSID number missing";
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*p++ = ' ' << 1;
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}
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else
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{
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*p++ = b[i] << 1;
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}
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}
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else
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{
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*p++ = ' ' << 1;
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}
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}
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*p++ = crrl | (ssid << 1);
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return p;
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}
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bool PacketModSource::bitsValid()
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{
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return m_bitCount > 0;
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}
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int PacketModSource::getBit()
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{
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int bit;
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if (m_bitCount > 0)
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{
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bit = (m_bits[m_byteIdx] >> m_bitIdx) & 1;
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m_bitIdx++;
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m_bitCount--;
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if (m_bitIdx == 8)
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{
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m_byteIdx++;
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m_bitIdx = 0;
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}
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}
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else
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bit = 0;
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return bit;
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}
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void PacketModSource::addBit(int bit)
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{
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// Transmit LSB first
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m_bits[m_byteIdx] |= bit << m_bitIdx;
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m_bitIdx++;
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m_bitCount++;
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m_bitCountTotal++;
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if (m_bitIdx == 8)
|
|
{
|
|
m_byteIdx++;
|
|
m_bits[m_byteIdx] = 0;
|
|
m_bitIdx = 0;
|
|
}
|
|
m_last5Bits = ((m_last5Bits << 1) | bit) & 0x1f;
|
|
}
|
|
|
|
void PacketModSource::initTX()
|
|
{
|
|
m_byteIdx = 0;
|
|
m_bitIdx = 0;
|
|
m_bitCount = m_bitCountTotal; // Reset to allow retransmission
|
|
m_nrziBit = 0;
|
|
if (m_settings.m_rampUpBits == 0)
|
|
{
|
|
m_state = tx;
|
|
m_pow = 0.0f;
|
|
}
|
|
else
|
|
{
|
|
m_state = ramp_up;
|
|
m_pow = -(Real)m_settings.m_rampRange;
|
|
m_powRamp = m_settings.m_rampRange/(m_settings.m_rampUpBits * (Real)m_samplesPerSymbol);
|
|
}
|
|
m_scrambler.init();
|
|
}
|
|
|
|
void PacketModSource::addTXPacket(QString callsign, QString to, QString via, QString data)
|
|
{
|
|
uint8_t packet[AX25_MAX_BYTES];
|
|
uint8_t *crc_start;
|
|
uint8_t *p;
|
|
crc16x25 crc;
|
|
uint16_t crcValue;
|
|
int len;
|
|
int packet_length;
|
|
|
|
// Create AX.25 packet
|
|
p = packet;
|
|
// Flag
|
|
for (int i = 0; i < std::min(m_settings.m_ax25PreFlags, AX25_MAX_FLAGS); i++)
|
|
*p++ = AX25_FLAG;
|
|
crc_start = p;
|
|
// Dest
|
|
p = ax25_address(p, to, 0xe0);
|
|
// From
|
|
p = ax25_address(p, callsign, 0x60);
|
|
// Via
|
|
p = ax25_address(p, via, 0x61);
|
|
// Control
|
|
*p++ = m_settings.m_ax25Control;
|
|
// PID
|
|
*p++ = m_settings.m_ax25PID;
|
|
// Data
|
|
len = data.length();
|
|
memcpy(p, data.toUtf8(), len);
|
|
p += len;
|
|
// CRC (do not include flags)
|
|
crc.calculate(crc_start, p-crc_start);
|
|
crcValue = crc.get();
|
|
*p++ = crcValue & 0xff;
|
|
*p++ = (crcValue >> 8);
|
|
// Flag
|
|
for (int i = 0; i < std::min(m_settings.m_ax25PostFlags, AX25_MAX_FLAGS); i++)
|
|
*p++ = AX25_FLAG;
|
|
|
|
packet_length = p-&packet[0];
|
|
|
|
// HDLC bit stuffing
|
|
m_byteIdx = 0;
|
|
m_bitIdx = 0;
|
|
m_last5Bits = 0;
|
|
m_bitCount = 0;
|
|
m_bitCountTotal = 0;
|
|
for (int i = 0; i < packet_length; i++)
|
|
{
|
|
for (int j = 0; j < 8; j++)
|
|
{
|
|
int tx_bit = (packet[i] >> j) & 1;
|
|
// Stuff 0 if last 5 bits are 1s
|
|
if ((packet[i] != AX25_FLAG) && (m_last5Bits == 0x1f))
|
|
addBit(0);
|
|
addBit(tx_bit);
|
|
}
|
|
}
|
|
m_samplesPerSymbol = m_channelSampleRate / m_settings.m_baud;
|
|
m_packetRepeatCount = m_settings.m_repeatCount;
|
|
initTX();
|
|
// Only reset phases at start of new packet TX, not in initTX(), so that
|
|
// there isn't a discontinuity in phase when repeatedly transmitting a
|
|
// single tone
|
|
m_sampleIdx = 0;
|
|
m_audioPhase = 0.0f;
|
|
m_fmPhase = 0.0;
|
|
|
|
if (m_settings.m_writeToFile)
|
|
m_audioFile.open("packetmod.csv", std::ofstream::out);
|
|
else if (m_audioFile.is_open())
|
|
m_audioFile.close();
|
|
}
|