mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-23 08:28:36 -05:00
340 lines
12 KiB
C++
340 lines
12 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
|
|
// Copyright (C) 2019 Edouard Griffiths, F4EXB //
|
|
// Copyright (C) 2021 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 "dsp/dspengine.h"
|
|
#include "dsp/datafifo.h"
|
|
#include "util/db.h"
|
|
#include "util/stepfunctions.h"
|
|
#include "pipes/pipeendpoint.h"
|
|
#include "maincore.h"
|
|
|
|
#include "packetdemod.h"
|
|
#include "packetdemodsink.h"
|
|
|
|
PacketDemodSink::PacketDemodSink(PacketDemod *packetDemod) :
|
|
m_packetDemod(packetDemod),
|
|
m_channelSampleRate(PACKETDEMOD_CHANNEL_SAMPLE_RATE),
|
|
m_channelFrequencyOffset(0),
|
|
m_magsqSum(0.0f),
|
|
m_magsqPeak(0.0f),
|
|
m_magsqCount(0),
|
|
m_messageQueueToChannel(nullptr),
|
|
m_f1(nullptr),
|
|
m_f0(nullptr),
|
|
m_corrBuf(nullptr),
|
|
m_corrIdx(0),
|
|
m_corrCnt(0)
|
|
{
|
|
m_magsq = 0.0;
|
|
|
|
m_demodBuffer.resize(1<<12);
|
|
m_demodBufferFill = 0;
|
|
|
|
applySettings(m_settings, true);
|
|
applyChannelSettings(m_channelSampleRate, m_channelFrequencyOffset, true);
|
|
}
|
|
|
|
PacketDemodSink::~PacketDemodSink()
|
|
{
|
|
delete[] m_f1;
|
|
delete[] m_f0;
|
|
delete[] m_corrBuf;
|
|
}
|
|
|
|
void PacketDemodSink::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 PacketDemodSink::processOneSample(Complex &ci)
|
|
{
|
|
Complex ca;
|
|
|
|
// FM demodulation
|
|
double magsqRaw;
|
|
Real deviation;
|
|
Real fmDemod = m_phaseDiscri.phaseDiscriminatorDelta(ci, magsqRaw, deviation);
|
|
|
|
// Calculate average and peak levels for level meter
|
|
Real magsq = magsqRaw / (SDR_RX_SCALED*SDR_RX_SCALED);
|
|
m_movingAverage(magsq);
|
|
m_magsq = m_movingAverage.asDouble();
|
|
m_magsqSum += magsq;
|
|
if (magsq > m_magsqPeak)
|
|
{
|
|
m_magsqPeak = magsq;
|
|
}
|
|
m_magsqCount++;
|
|
|
|
m_corrBuf[m_corrIdx] = fmDemod;
|
|
if (m_corrCnt >= m_correlationLength)
|
|
{
|
|
// Correlate with 1200 + 2200 baud complex exponentials
|
|
Complex corrF0 = 0.0f;
|
|
Complex corrF1 = 0.0f;
|
|
for (int i = 0; i < m_correlationLength; i++)
|
|
{
|
|
int j = m_corrIdx - i;
|
|
if (j < 0)
|
|
j += m_correlationLength;
|
|
corrF0 += m_f0[i] * m_corrBuf[j];
|
|
corrF1 += m_f1[i] * m_corrBuf[j];
|
|
}
|
|
m_corrCnt--; // Avoid overflow in increment below
|
|
|
|
// Low pass filter, to minimize changes above the baud rate
|
|
Real f0Filt = m_lowpassF0.filter(std::abs(corrF0));
|
|
Real f1Filt = m_lowpassF1.filter(std::abs(corrF1));
|
|
|
|
// Determine which is the closest match and then quantise to 1 or -1
|
|
// FIXME: We should try to account for the fact that higher frequencies can have preemphasis
|
|
float diff = f1Filt - f0Filt;
|
|
int sample = diff >= 0.0f ? 1 : 0;
|
|
|
|
// Look for edge
|
|
if (sample != m_samplePrev)
|
|
{
|
|
m_syncCount = PACKETDEMOD_CHANNEL_SAMPLE_RATE/m_settings.m_baud/2;
|
|
}
|
|
else
|
|
{
|
|
m_syncCount--;
|
|
if (m_syncCount <= 0)
|
|
{
|
|
// HDLC deframing
|
|
|
|
// Should be in the middle of the symbol
|
|
// NRZI decoding
|
|
int bit;
|
|
if (sample != m_symbolPrev)
|
|
bit = 0;
|
|
else
|
|
bit = 1;
|
|
m_symbolPrev = sample;
|
|
|
|
// Store in shift reg
|
|
m_bits |= bit << m_bitCount;
|
|
m_bitCount++;
|
|
|
|
if (bit == 1)
|
|
{
|
|
m_onesCount++;
|
|
// Shouldn't ever get 7 1s in a row
|
|
if ((m_onesCount == 7) && m_gotSOP)
|
|
{
|
|
m_gotSOP = false;
|
|
m_byteCount = 0;
|
|
}
|
|
}
|
|
else if (bit == 0)
|
|
{
|
|
if (m_onesCount == 5)
|
|
{
|
|
// Remove bit-stuffing (5 1s followed by a 0)
|
|
m_bitCount--;
|
|
}
|
|
else if (m_onesCount == 6)
|
|
{
|
|
// Start/end of packet
|
|
if ((m_bitCount == 8) && (m_bits == 0x7e) && (m_byteCount > 0))
|
|
{
|
|
// End of packet
|
|
// Check CRC is valid
|
|
m_crc.init();
|
|
m_crc.calculate(m_bytes, m_byteCount - 2);
|
|
uint16_t calcCrc = m_crc.get();
|
|
uint16_t rxCrc = m_bytes[m_byteCount-2] | (m_bytes[m_byteCount-1] << 8);
|
|
if (calcCrc == rxCrc)
|
|
{
|
|
QByteArray rxPacket((char *)m_bytes, m_byteCount);
|
|
qDebug() << "RX: " << rxPacket.toHex();
|
|
if (getMessageQueueToChannel())
|
|
{
|
|
MainCore::MsgPacket *msg = MainCore::MsgPacket::create(m_packetDemod, rxPacket, QDateTime::currentDateTime()); // FIXME pointer
|
|
getMessageQueueToChannel()->push(msg);
|
|
}
|
|
}
|
|
else
|
|
qDebug() << QString("CRC mismatch: %1 %2").arg(calcCrc, 4, 16, QLatin1Char('0')).arg(rxCrc, 4, 16, QLatin1Char('0'));
|
|
// Reset state to start receiving next packet
|
|
m_gotSOP = false;
|
|
m_bits = 0;
|
|
m_bitCount = 0;
|
|
m_byteCount = 0;
|
|
}
|
|
else
|
|
{
|
|
// Start of packet
|
|
m_gotSOP = true;
|
|
m_bits = 0;
|
|
m_bitCount = 0;
|
|
m_byteCount = 0;
|
|
}
|
|
}
|
|
m_onesCount = 0;
|
|
}
|
|
|
|
if (m_gotSOP)
|
|
{
|
|
if (m_bitCount == 8)
|
|
{
|
|
if (m_byteCount >= 512)
|
|
{
|
|
// Too many bytes
|
|
m_gotSOP = false;
|
|
m_byteCount = 0;
|
|
}
|
|
else
|
|
{
|
|
m_bytes[m_byteCount] = m_bits;
|
|
m_byteCount++;
|
|
}
|
|
m_bits = 0;
|
|
m_bitCount = 0;
|
|
}
|
|
}
|
|
m_syncCount = PACKETDEMOD_CHANNEL_SAMPLE_RATE/m_settings.m_baud;
|
|
}
|
|
}
|
|
m_samplePrev = sample;
|
|
}
|
|
m_corrIdx = (m_corrIdx + 1) % m_correlationLength;
|
|
m_corrCnt++;
|
|
|
|
m_demodBuffer[m_demodBufferFill++] = fmDemod * std::numeric_limits<int16_t>::max();
|
|
|
|
if (m_demodBufferFill >= m_demodBuffer.size())
|
|
{
|
|
QList<DataFifo*> *dataFifos = MainCore::instance()->getDataPipes().getFifos(m_channel, "demod");
|
|
|
|
if (dataFifos)
|
|
{
|
|
QList<DataFifo*>::iterator it = dataFifos->begin();
|
|
|
|
for (; it != dataFifos->end(); ++it) {
|
|
(*it)->write((quint8*) &m_demodBuffer[0], m_demodBuffer.size() * sizeof(qint16));
|
|
}
|
|
}
|
|
|
|
m_demodBufferFill = 0;
|
|
}
|
|
}
|
|
|
|
void PacketDemodSink::applyChannelSettings(int channelSampleRate, int channelFrequencyOffset, bool force)
|
|
{
|
|
qDebug() << "PacketDemodSink::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, m_settings.m_rfBandwidth / 2.2);
|
|
m_interpolatorDistance = (Real) channelSampleRate / (Real) PACKETDEMOD_CHANNEL_SAMPLE_RATE;
|
|
m_interpolatorDistanceRemain = m_interpolatorDistance;
|
|
}
|
|
|
|
m_channelSampleRate = channelSampleRate;
|
|
m_channelFrequencyOffset = channelFrequencyOffset;
|
|
}
|
|
|
|
void PacketDemodSink::applySettings(const PacketDemodSettings& settings, bool force)
|
|
{
|
|
qDebug() << "PacketDemodSink::applySettings:"
|
|
<< " force: " << force;
|
|
|
|
if ((settings.m_rfBandwidth != m_settings.m_rfBandwidth) || force)
|
|
{
|
|
m_interpolator.create(16, m_channelSampleRate, settings.m_rfBandwidth / 2.2);
|
|
m_interpolatorDistance = (Real) m_channelSampleRate / (Real) PACKETDEMOD_CHANNEL_SAMPLE_RATE;
|
|
m_interpolatorDistanceRemain = m_interpolatorDistance;
|
|
m_lowpass.create(301, PACKETDEMOD_CHANNEL_SAMPLE_RATE, settings.m_rfBandwidth / 2.0f);
|
|
}
|
|
if ((settings.m_fmDeviation != m_settings.m_fmDeviation) || force)
|
|
{
|
|
m_phaseDiscri.setFMScaling(PACKETDEMOD_CHANNEL_SAMPLE_RATE / (2.0f * settings.m_fmDeviation));
|
|
}
|
|
|
|
if (force)
|
|
{
|
|
delete[] m_f1;
|
|
delete[] m_f0;
|
|
delete[] m_corrBuf;
|
|
m_correlationLength = PACKETDEMOD_CHANNEL_SAMPLE_RATE/settings.m_baud;
|
|
m_f1 = new Complex[m_correlationLength]();
|
|
m_f0 = new Complex[m_correlationLength]();
|
|
m_corrBuf = new Complex[m_correlationLength]();
|
|
m_corrIdx = 0;
|
|
m_corrCnt = 0;
|
|
Real f0 = 0.0f;
|
|
Real f1 = 0.0f;
|
|
for (int i = 0; i < m_correlationLength; i++)
|
|
{
|
|
m_f0[i] = Complex(cos(f0), sin(f0));
|
|
m_f1[i] = Complex(cos(f1), sin(f1));
|
|
f0 += 2.0f*(Real)M_PI*2200.0f/PACKETDEMOD_CHANNEL_SAMPLE_RATE;
|
|
f1 += 2.0f*(Real)M_PI*1200.0f/PACKETDEMOD_CHANNEL_SAMPLE_RATE;
|
|
}
|
|
|
|
m_lowpassF1.create(301, PACKETDEMOD_CHANNEL_SAMPLE_RATE, settings.m_baud * 1.1f);
|
|
m_lowpassF0.create(301, PACKETDEMOD_CHANNEL_SAMPLE_RATE, settings.m_baud * 1.1f);
|
|
m_samplePrev = 0;
|
|
m_syncCount = 0;
|
|
m_symbolPrev = 0;
|
|
m_bits = 0;
|
|
m_bitCount = 0;
|
|
m_onesCount = 0;
|
|
m_gotSOP = false;
|
|
m_byteCount = 0;
|
|
}
|
|
|
|
m_settings = settings;
|
|
}
|