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sdrangel/plugins/channeltx/modpsk31/psk31modsource.cpp

421 lines
12 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2023 Jon Beniston, M7RCE <jon@beniston.com> //
// //
// 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 <cctype>
#include <QDebug>
#include "dsp/basebandsamplesink.h"
#include "dsp/datafifo.h"
#include "psk31mod.h"
#include "psk31modsource.h"
#include "util/messagequeue.h"
#include "maincore.h"
PSK31Source::PSK31Source() :
m_channelSampleRate(48000),
m_channelFrequencyOffset(0),
m_spectrumRate(2000),
m_spectrumSink(nullptr),
m_specSampleBufferIndex(0),
m_magsq(0.0),
m_levelCalcCount(0),
m_peakLevel(0.0f),
m_levelSum(0.0f),
m_byteIdx(0),
m_bitIdx(0),
m_bitCount(0)
{
m_bits.append(0);
m_lowpass.create(301, m_channelSampleRate, 100.0 / 2.0);
m_pulseShape.create(0.5, 6, m_channelSampleRate / 31.25, true);
m_demodBuffer.resize(1<<12);
m_demodBufferFill = 0;
m_specSampleBuffer.resize(m_specSampleBufferSize);
m_interpolatorDistanceRemain = 0;
m_interpolatorConsumed = false;
m_interpolatorDistance = (Real)m_channelSampleRate / (Real)m_spectrumRate;
m_interpolator.create(48, m_spectrumRate, m_spectrumRate / 2.2, 3.0);
applySettings(m_settings, true);
applyChannelSettings(m_channelSampleRate, m_channelFrequencyOffset, true);
}
PSK31Source::~PSK31Source()
{
}
void PSK31Source::pull(SampleVector::iterator begin, unsigned int nbSamples)
{
std::for_each(
begin,
begin + nbSamples,
[this](Sample& s) {
pullOne(s);
}
);
}
void PSK31Source::pullOne(Sample& sample)
{
if (m_settings.m_channelMute)
{
sample.m_real = 0.0f;
sample.m_imag = 0.0f;
return;
}
// Calculate next sample
modulateSample();
// Shift to carrier frequency
Complex ci = m_modSample;
ci *= m_carrierNco.nextIQ();
// Calculate power
double magsq = ci.real() * ci.real() + ci.imag() * ci.imag();
m_movingAverage(magsq);
m_magsq = m_movingAverage.asDouble();
// Convert from float to fixed point
sample.m_real = (FixReal) (ci.real() * SDR_TX_SCALEF);
sample.m_imag = (FixReal) (ci.imag() * SDR_TX_SCALEF);
}
void PSK31Source::sampleToSpectrum(Complex sample)
{
if (m_spectrumSink)
{
Complex out;
if (m_interpolator.decimate(&m_interpolatorDistanceRemain, sample, &out))
{
m_interpolatorDistanceRemain += m_interpolatorDistance;
Real r = std::real(out) * SDR_TX_SCALEF;
Real i = std::imag(out) * SDR_TX_SCALEF;
m_specSampleBuffer[m_specSampleBufferIndex++] = Sample(r, i);
if (m_specSampleBufferIndex == m_specSampleBufferSize)
{
m_spectrumSink->feed(m_specSampleBuffer.begin(), m_specSampleBuffer.end(), false);
m_specSampleBufferIndex = 0;
}
}
}
}
void PSK31Source::modulateSample()
{
Real mod;
if (m_sampleIdx == 0)
{
if (m_bitCount == 0)
{
if (!m_textToTransmit.isEmpty())
{
// Encode a character at a time, so we get a TxReport after each character
QString s = m_textToTransmit.left(1);
m_textToTransmit = m_textToTransmit.mid(1);
encodeText(s);
}
else
{
encodeIdle();
}
initTX();
}
m_bit = getBit();
// Differential encoding
m_prevSymbol = m_symbol;
m_symbol = (m_bit ^ m_symbol) ? 0 : 1;
}
// PSK
if (m_settings.m_pulseShaping)
{
if (m_sampleIdx == 1) {
mod = m_pulseShape.filter(m_symbol ? 1.0f : -1.0f);
} else {
mod = m_pulseShape.filter(0.0f);
}
}
else
{
mod = m_symbol ? 1.0f : -1.0f;
}
m_sampleIdx++;
if (m_sampleIdx >= m_samplesPerSymbol) {
m_sampleIdx = 0;
}
if (!m_settings.m_rfNoise)
{
m_modSample.real(m_linearGain * mod);
m_modSample.imag(0.0f);
}
else
{
// Noise to test filter frequency response
m_modSample.real(m_linearGain * ((Real)rand()/((Real)RAND_MAX)-0.5f));
m_modSample.imag(m_linearGain * ((Real)rand()/((Real)RAND_MAX)-0.5f));
}
// Apply low pass filter to limit RF BW
m_modSample = m_lowpass.filter(m_modSample);
// Display in spectrum analyser
sampleToSpectrum(m_modSample);
Real s = std::real(m_modSample);
calculateLevel(s);
// Send to demod analyser
m_demodBuffer[m_demodBufferFill] = mod * std::numeric_limits<int16_t>::max();
++m_demodBufferFill;
if (m_demodBufferFill >= m_demodBuffer.size())
{
QList<ObjectPipe*> dataPipes;
MainCore::instance()->getDataPipes().getDataPipes(m_channel, "demod", dataPipes);
if (dataPipes.size() > 0)
{
QList<ObjectPipe*>::iterator it = dataPipes.begin();
for (; it != dataPipes.end(); ++it)
{
DataFifo *fifo = qobject_cast<DataFifo*>((*it)->m_element);
if (fifo) {
fifo->write((quint8*) &m_demodBuffer[0], m_demodBuffer.size() * sizeof(qint16), DataFifo::DataTypeI16);
}
}
}
m_demodBufferFill = 0;
}
}
void PSK31Source::calculateLevel(Real& sample)
{
if (m_levelCalcCount < m_levelNbSamples)
{
m_peakLevel = std::max(std::fabs(m_peakLevel), sample);
m_levelSum += sample * sample;
m_levelCalcCount++;
}
else
{
m_rmsLevel = sqrt(m_levelSum / m_levelNbSamples);
m_peakLevelOut = m_peakLevel;
m_peakLevel = 0.0f;
m_levelSum = 0.0f;
m_levelCalcCount = 0;
}
}
void PSK31Source::applySettings(const PSK31Settings& settings, bool force)
{
if ((settings.m_baud != m_settings.m_baud) || force)
{
m_samplesPerSymbol = m_channelSampleRate / settings.m_baud;
qDebug() << "m_samplesPerSymbol: " << m_samplesPerSymbol << " (" << m_channelSampleRate << "/" << settings.m_baud << ")";
}
if ((settings.m_lpfTaps != m_settings.m_lpfTaps) || (settings.m_rfBandwidth != m_settings.m_rfBandwidth) || force)
{
qDebug() << "PSK31Source::applySettings: Creating new lpf with taps " << settings.m_lpfTaps << " rfBW " << settings.m_rfBandwidth;
m_lowpass.create(settings.m_lpfTaps, m_channelSampleRate, settings.m_rfBandwidth / 2.0);
}
if ((settings.m_beta != m_settings.m_beta) || (settings.m_symbolSpan != m_settings.m_symbolSpan) || (settings.m_baud != m_settings.m_baud) || force)
{
qDebug() << "PSK31Source::applySettings: Recreating pulse shaping filter: "
<< " beta: " << settings.m_beta
<< " symbolSpan: " << settings.m_symbolSpan
<< " channelSampleRate:" << m_channelSampleRate
<< " baud:" << settings.m_baud;
m_pulseShape.create(settings.m_beta, settings.m_symbolSpan, m_channelSampleRate/settings.m_baud, true);
}
m_settings = settings;
m_linearGain = powf(10.0f, m_settings.m_gain/20.0f);
}
void PSK31Source::applyChannelSettings(int channelSampleRate, int channelFrequencyOffset, bool force)
{
qDebug() << "PSK31Source::applyChannelSettings:"
<< " channelSampleRate: " << channelSampleRate
<< " channelFrequencyOffset: " << channelFrequencyOffset
<< " rfBandwidth: " << m_settings.m_rfBandwidth;
if ((channelFrequencyOffset != m_channelFrequencyOffset)
|| (channelSampleRate != m_channelSampleRate) || force)
{
m_carrierNco.setFreq(channelFrequencyOffset, channelSampleRate);
}
if ((m_channelSampleRate != channelSampleRate) || force)
{
qDebug() << "PSK31Source::applyChannelSettings: Recreating filters";
m_lowpass.create(m_settings.m_lpfTaps, channelSampleRate, m_settings.m_rfBandwidth / 2.0);
qDebug() << "PSK31Source::applyChannelSettings: Recreating bandpass filter: "
<< " channelSampleRate:" << channelSampleRate;
qDebug() << "PSK31Source::applyChannelSettings: Recreating pulse shaping filter: "
<< " beta: " << m_settings.m_beta
<< " symbolSpan: " << m_settings.m_symbolSpan
<< " channelSampleRate:" << m_channelSampleRate
<< " baud:" << m_settings.m_baud;
m_pulseShape.create(m_settings.m_beta, m_settings.m_symbolSpan, channelSampleRate/m_settings.m_baud, true);
}
if ((m_channelSampleRate != channelSampleRate) || force)
{
m_interpolatorDistanceRemain = 0;
m_interpolatorConsumed = false;
m_interpolatorDistance = (Real) channelSampleRate / (Real) m_spectrumRate;
m_interpolator.create(48, m_spectrumRate, m_spectrumRate / 2.2, 3.0);
}
m_channelSampleRate = channelSampleRate;
m_channelFrequencyOffset = channelFrequencyOffset;
m_samplesPerSymbol = m_channelSampleRate / m_settings.m_baud;
qDebug() << "m_samplesPerSymbol: " << m_samplesPerSymbol << " (" << m_channelSampleRate << "/" << m_settings.m_baud << ")";
QList<ObjectPipe*> pipes;
MainCore::instance()->getMessagePipes().getMessagePipes(m_channel, "reportdemod", pipes);
if (pipes.size() > 0)
{
for (const auto& pipe : pipes)
{
MessageQueue* messageQueue = qobject_cast<MessageQueue*>(pipe->m_element);
MainCore::MsgChannelDemodReport *msg = MainCore::MsgChannelDemodReport::create(m_channel, m_channelSampleRate);
messageQueue->push(msg);
}
}
}
int PSK31Source::getBit()
{
int bit;
if (m_bitCount > 0)
{
bit = (m_bits[m_byteIdx] >> m_bitIdx) & 1;
m_bitIdx++;
m_bitCount--;
if (m_bitIdx == 8)
{
m_byteIdx++;
m_bitIdx = 0;
}
}
else
{
qDebug() << "PSK31Source::getBit: Called when empty";
bit = 1;
}
return bit;
}
void PSK31Source::addBit(int bit)
{
m_bits[m_byteIdx] |= bit << m_bitIdx;
m_bitIdx++;
m_bitCount++;
if (m_bitIdx == 8)
{
m_byteIdx++;
if (m_bits.size() <= m_byteIdx) {
m_bits.append(0);
}
m_bitIdx = 0;
}
}
void PSK31Source::initTX()
{
m_byteIdx = 0;
m_bitIdx = 0;
}
void PSK31Source::addTXText(QString text)
{
int count = m_settings.m_repeat ? m_settings.m_repeatCount : 1;
for (int i = 0; i < count; i++) {
QString s = text;
if (m_settings.m_prefixCRLF) {
s.prepend("\r\r\n");
}
if (m_settings.m_postfixCRLF) {
s.append("\r\r\n");
}
m_textToTransmit.append(s);
}
}
void PSK31Source::encodeText(const QString& text)
{
// PSK31 varicode encoding
m_byteIdx = 0;
m_bitIdx = 0;
m_bitCount = 0;
for (int i = 0; i < m_bits.size(); i++) {
m_bits[i] = 0;
}
for (int i = 0; i < text.size(); i++)
{
unsigned bits;
unsigned bitCount;
m_psk31Encoder.encode(text[i], bits, bitCount);
for (unsigned int j = 0; j < bitCount; j++)
{
int txBit = (bits >> j) & 1;
addBit(txBit);
}
}
if (getMessageQueueToGUI())
{
PSK31::MsgReportTx* msg = PSK31::MsgReportTx::create(text, m_textToTransmit.size());
getMessageQueueToGUI()->push(msg);
}
}
void PSK31Source::encodeIdle()
{
m_byteIdx = 0;
m_bitIdx = 0;
m_bitCount = 0;
for (int i = 0; i < m_bits.size(); i++) {
m_bits[i] = 0;
}
addBit(0);
addBit(0);
}