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sdrangel/plugins/channelrx/freqscanner/freqscannersink.cpp
2024-04-20 19:10:18 +02:00

267 lines
10 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 <QDebug>
#include <complex.h>
#include "dsp/dspengine.h"
#include "dsp/fftfactory.h"
#include "util/db.h"
#include "freqscanner.h"
#include "freqscannersink.h"
FreqScannerSink::FreqScannerSink(FreqScanner *ilsDemod) :
m_freqScanner(ilsDemod),
m_channel(nullptr),
m_channelSampleRate(48000),
m_channelFrequencyOffset(0),
m_scannerSampleRate(33320),
m_centerFrequency(0),
m_messageQueueToChannel(nullptr),
m_fftSequence(-1),
m_fft(nullptr),
m_fftCounter(0),
m_fftSize(1024),
m_binsPerChannel(16),
m_averageCount(0)
{
applySettings(m_settings, QStringList(), true);
applyChannelSettings(m_channelSampleRate, m_channelFrequencyOffset, 16, 4, true);
}
FreqScannerSink::~FreqScannerSink()
{
}
void FreqScannerSink::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 (and filter)
{
if (m_interpolator.decimate(&m_interpolatorDistanceRemain, c, &ci))
{
processOneSample(ci);
m_interpolatorDistanceRemain += m_interpolatorDistance;
}
}
}
}
void FreqScannerSink::processOneSample(Complex &ci)
{
ci /= SDR_RX_SCALEF;
m_fft->in()[m_fftCounter] = ci;
m_fftCounter++;
if (m_fftCounter == m_fftSize)
{
// Apply windowing function
m_fftWindow.apply(m_fft->in());
// Perform FFT
m_fft->transform();
// Reorder (so negative frequencies are first) and average
int halfSize = m_fftSize / 2;
for (int i = 0; i < halfSize; i++) {
m_fftAverage.storeAndGetAvg(m_magSq[i], magSq(i + halfSize), i);
}
for (int i = 0; i < halfSize; i++) {
m_fftAverage.storeAndGetAvg(m_magSq[i + halfSize], magSq(i), i + halfSize);
}
if (m_fftAverage.nextAverage())
{
// Send results to channel
if (getMessageQueueToChannel() && (m_settings.m_channelBandwidth != 0) && (m_binsPerChannel != 0))
{
FreqScanner::MsgScanResult* msg = FreqScanner::MsgScanResult::create(m_fftStartTime);
QList<FreqScanner::MsgScanResult::ScanResult>& results = msg->getScanResults();
for (int i = 0; i < m_settings.m_frequencySettings.size(); i++)
{
if (m_settings.m_frequencySettings[i].m_enabled)
{
qint64 frequency = m_settings.m_frequencySettings[i].m_frequency;
qint64 startFrequency = m_centerFrequency - m_scannerSampleRate / 2;
qint64 diff = frequency - startFrequency;
float binBW = m_scannerSampleRate / (float)m_fftSize;
// Ignore results in uppper and lower 12.5%, as there may be aliasing here from half-band filters
if ((diff < m_scannerSampleRate * 0.875f) && (diff >= m_scannerSampleRate * 0.125f))
{
int bin = std::round(diff / binBW);
int channelBins;
if (m_settings.m_frequencySettings[i].m_channelBandwidth.isEmpty())
{
channelBins = m_binsPerChannel;
}
else
{
int channelBW = m_settings.getChannelBandwidth(&m_settings.m_frequencySettings[i]);
channelBins = m_fftSize / (m_scannerSampleRate / (float)channelBW);
}
// Calculate power at that frequency
Real power;
if (m_settings.m_measurement == FreqScannerSettings::PEAK) {
power = peakPower(bin, channelBins);
} else {
power = totalPower(bin, channelBins);
}
//qDebug() << "startFrequency:" << startFrequency << "m_scannerSampleRate:" << m_scannerSampleRate << "m_centerFrequency:" << m_centerFrequency << "frequency" << frequency << "bin" << bin << "power" << power;
FreqScanner::MsgScanResult::ScanResult result = {frequency, power};
results.append(result);
}
}
}
getMessageQueueToChannel()->push(msg);
}
m_averageCount = 0;
m_fftStartTime = QDateTime::currentDateTime();
}
m_fftCounter = 0;
}
}
// Calculate total power in a channel containing the specified bin (i.e. sums adjacent bins in the same channel)
Real FreqScannerSink::totalPower(int bin, int channelBins) const
{
// Skip bin between halfway between channels
// Then skip first and last bins, to avoid spectral leakage (particularly at DC)
int startBin = bin - channelBins / 2 + 1 + 1;
Real magSqSum = 0.0f;
for (int i = 0; i < channelBins - 2 - 1; i++) {
int idx = startBin + i;
if ((idx < 0) || (idx >= m_fftSize)) {
continue;
}
magSqSum += m_magSq[idx];
}
Real db = CalcDb::dbPower(magSqSum);
return db;
}
// Calculate peak power in a channel containing the specified bin
Real FreqScannerSink::peakPower(int bin, int channelBins) const
{
// Skip bin between halfway between channels
// Then skip first and last bins, to avoid spectral leakage (particularly at DC)
int startBin = bin - channelBins/2 + 1 + 1;
Real maxMagSq = std::numeric_limits<Real>::min();
for (int i = 0; i < channelBins - 2 - 1; i++)
{
int idx = startBin + i;
if ((idx < 0) || (idx >= m_fftSize)) {
continue;
}
//qDebug() << "idx:" << idx << "power:" << CalcDb::dbPower(m_magSq[idx]);
maxMagSq = std::max(maxMagSq, m_magSq[idx]);
}
Real db = CalcDb::dbPower(maxMagSq);
return db;
}
Real FreqScannerSink::magSq(int bin) const
{
Complex c = m_fft->out()[bin];
Real v = c.real() * c.real() + c.imag() * c.imag();
Real magsq = v / (m_fftSize * m_fftSize);
return magsq;
}
void FreqScannerSink::applyChannelSettings(int channelSampleRate, int channelFrequencyOffset, int scannerSampleRate, int fftSize, int binsPerChannel, bool force)
{
qDebug() << "FreqScannerSink::applyChannelSettings:"
<< " channelSampleRate: " << channelSampleRate
<< " channelFrequencyOffset: " << channelFrequencyOffset
<< " scannerSampleRate: " << scannerSampleRate
<< " fftSize: " << fftSize
<< " binsPerChannel: " << binsPerChannel;
if ((m_channelFrequencyOffset != channelFrequencyOffset) ||
(m_channelSampleRate != channelSampleRate) || force)
{
m_nco.setFreq(-channelFrequencyOffset, channelSampleRate);
}
if ((m_channelSampleRate != channelSampleRate) || (m_scannerSampleRate != scannerSampleRate) || force)
{
m_interpolator.create(16, channelSampleRate, scannerSampleRate / 2.2); // Filter potential aliasing resulting from half-band filters
m_interpolatorDistance = (Real) channelSampleRate / (Real)scannerSampleRate;
m_interpolatorDistanceRemain = m_interpolatorDistance;
}
if ((m_fftSize != fftSize) || force)
{
FFTFactory* fftFactory = DSPEngine::instance()->getFFTFactory();
if (m_fftSequence >= 0) {
fftFactory->releaseEngine(fftSize, false, m_fftSequence);
}
m_fftSequence = fftFactory->getEngine(fftSize, false, &m_fft);
m_fftCounter = 0;
m_fftStartTime = QDateTime::currentDateTime();
m_fftWindow.create(FFTWindow::Hanning, fftSize);
int averages = m_settings.m_scanTime * scannerSampleRate / 2 / fftSize;
m_fftAverage.resize(fftSize, averages);
m_magSq.resize(fftSize);
}
m_channelSampleRate = channelSampleRate;
m_channelFrequencyOffset = channelFrequencyOffset;
m_scannerSampleRate = scannerSampleRate;
m_fftSize = fftSize;
m_binsPerChannel = binsPerChannel;
}
void FreqScannerSink::applySettings(const FreqScannerSettings& settings, const QStringList& settingsKeys, bool force)
{
qDebug() << "FreqScannerSink::applySettings:"
<< settings.getDebugString(settingsKeys, force)
<< " force: " << force;
if (settingsKeys.contains("scanTime") || force)
{
int averages = settings.m_scanTime * m_scannerSampleRate / 2 / m_fftSize;
m_fftAverage.resize(m_fftSize, averages);
}
if (force) {
m_settings = settings;
} else {
m_settings.applySettings(settingsKeys, settings);
}
}