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Freq scanner VAD: CW mitigation

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f4exb
2026-02-21 05:15:43 +01:00
parent 6a56c25dd0
commit e6ff9669a9
3 changed files with 102 additions and 16 deletions
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plugins/channelrx/freqscanner/freqscanner.cpp
+1 -1
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@@ -693,7 +693,7 @@ void FreqScanner::processScanResults(const QDateTime& fftStartTime, const QList<
&& checkVoiceThreshold(m_settings.m_voiceSquelchType, results[i].m_voiceActivityLevel, m_settings.m_voiceSquelchThreshold))
{
if (m_settings.m_voiceSquelchType != FreqScannerSettings::VoiceSquelchType::None) {
qDebug("FreqScanner::processScanResults: WAIT_FOR_RETRANSMISSION restart: voice score: %f", results[i].m_voiceActivityLevel);
qDebug("FreqScanner::processScanResults: WAIT_FOR_RETRANSMISSION restart: frequency: %lld, voice score: %f", m_activeFrequency, results[i].m_voiceActivityLevel);
}
m_timeoutTimer.stop();
m_state = WAIT_FOR_END_TX;
plugins/channelrx/freqscanner/freqscannersink.cpp
+100 -14
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@@ -155,9 +155,9 @@ void FreqScannerSink::processOneSample(Complex &ci)
Real voiceLevel = 0.0;
if (m_settings.m_voiceSquelchType == FreqScannerSettings::VoiceLsb) {
voiceLevel = voiceActivityLevel(frequency, bin, channelBins, true);
voiceLevel = voiceActivityLevel(bin, channelBins, true);
} else if (m_settings.m_voiceSquelchType == FreqScannerSettings::VoiceUsb) {
voiceLevel = voiceActivityLevel(frequency, bin, channelBins, false);
voiceLevel = voiceActivityLevel(bin, channelBins, false);
}
if (voiceLevel > 0.0) {
@@ -417,7 +417,7 @@ void FreqScannerSink::applySettings(const FreqScannerSettings& settings, const Q
// Voice activity detection for SSB signals
// Detects voice by looking for formant-like structure using spectral smoothing
// Returns a value from 0.0 (no voice) to 1.0 (strong voice signature)
Real FreqScannerSink::voiceActivityLevel(qint64 freq, int bin, int channelBins, bool isLSB)
Real FreqScannerSink::voiceActivityLevel(int bin, int channelBins, bool isLSB)
{
// Voice band in SSB is typically 100-3000 Hz from carrier
// We look for 2-4 formant peaks in the smoothed spectral envelope
@@ -634,6 +634,100 @@ Real FreqScannerSink::voiceActivityLevel(qint64 freq, int bin, int channelBins,
return 0.0; // No F2 formant - not voice or mistuned
}
// Reject strongly tonal spectra (typical CW / single-tone signals).
// Voice in SSB should have broader spectral spread, lower peak dominance,
// and non-negligible spectral flatness across the 100-3000 Hz voice band.
Real voiceBandTotalEnergy = 0.0;
Real voiceBandPeakEnergy = 0.0;
Real voiceBandSecondPeakEnergy = 0.0;
Real voiceBandLogEnergySum = 0.0;
Real voiceBandWeightedFreqSum = 0.0;
Real voiceBandWeightedFreqSqSum = 0.0;
QVector<Real> voiceBandEnergies;
voiceBandEnergies.reserve(std::max(0, endBin - startBin + 1));
int voiceBandBins = 0;
for (int absBin = startBin; absBin <= endBin; absBin++)
{
float signedOffset = (absBin - carrierBin) * binBW;
float voiceOffset = isLSB ? -signedOffset : signedOffset;
if (voiceOffset < 100.0f || voiceOffset > 3000.0f) {
continue;
}
Real binEnergy = magSqFromRawFFT(absBin);
Real safeEnergy = std::max(binEnergy, (Real) 1e-20);
voiceBandEnergies.append(safeEnergy);
voiceBandTotalEnergy += safeEnergy;
if (safeEnergy > voiceBandPeakEnergy)
{
voiceBandSecondPeakEnergy = voiceBandPeakEnergy;
voiceBandPeakEnergy = safeEnergy;
}
else if (safeEnergy > voiceBandSecondPeakEnergy)
{
voiceBandSecondPeakEnergy = safeEnergy;
}
voiceBandLogEnergySum += std::log(safeEnergy);
voiceBandWeightedFreqSum += safeEnergy * voiceOffset;
voiceBandWeightedFreqSqSum += safeEnergy * voiceOffset * voiceOffset;
voiceBandBins++;
}
if (voiceBandBins <= 0 || voiceBandTotalEnergy <= 0.0) {
return 0.0;
}
Real voiceBandMeanEnergy = voiceBandTotalEnergy / voiceBandBins;
Real voiceBandGeometricMean = std::exp(voiceBandLogEnergySum / voiceBandBins);
Real voiceBandMeanFreq = voiceBandWeightedFreqSum / voiceBandTotalEnergy;
Real voiceBandMeanFreqSq = voiceBandWeightedFreqSqSum / voiceBandTotalEnergy;
Real voiceBandVariance = std::max((Real) 0.0, voiceBandMeanFreqSq - voiceBandMeanFreq * voiceBandMeanFreq);
float voiceBandRmsSpreadHz = std::sqrt(voiceBandVariance);
float spectralFlatness = voiceBandMeanEnergy > 0.0 ? (voiceBandGeometricMean / voiceBandMeanEnergy) : 0.0f;
float peakFraction = voiceBandTotalEnergy > 0.0 ? (voiceBandPeakEnergy / voiceBandTotalEnergy) : 1.0f;
float peak12Ratio = voiceBandSecondPeakEnergy > 0.0 ? (voiceBandPeakEnergy / voiceBandSecondPeakEnergy) : 1000.0f;
int significantBins = 0;
Real significantThreshold = voiceBandMeanEnergy * 1.8;
for (const Real& binEnergy : voiceBandEnergies)
{
if (binEnergy > significantThreshold) {
significantBins++;
}
}
if ((peakFraction > 0.45f) || (spectralFlatness < 0.025f) || (significantBins < 5)) {
return 0.0;
}
// Additional strong-CW rejection:
// - very narrow energy spread in voice band
// - one dominant spectral line overwhelmingly larger than the second line
if ((voiceBandRmsSpreadHz < 220.0f) || ((peak12Ratio > 8.0f) && (significantBins < 9))) {
return 0.0;
}
float tonalPenalty = 1.0f;
if (peakFraction > 0.30f) {
tonalPenalty *= 0.6f;
}
if (spectralFlatness < 0.06f) {
tonalPenalty *= 0.7f;
}
if (voiceBandRmsSpreadHz < 350.0f) {
tonalPenalty *= 0.55f;
}
if (peak12Ratio > 4.0f) {
tonalPenalty *= 0.60f;
}
// CW rejection end
// Additional F1 plausibility checks.
// Prevent a tiny low-frequency ripple from being accepted as F1 when
// dominant formant energy is shifted high (e.g. around 2 kHz).
@@ -718,7 +812,7 @@ Real FreqScannerSink::voiceActivityLevel(qint64 freq, int bin, int channelBins,
if (voiceOffset >= 100.0f && voiceOffset <= 3000.0f)
{
rawNoiseFloor += m_magSq[absBin];
rawNoiseFloor += magSqFromRawFFT(absBin);
rawBinCount++;
}
}
@@ -737,7 +831,7 @@ Real FreqScannerSink::voiceActivityLevel(qint64 freq, int bin, int channelBins,
continue;
}
Real binEnergy = m_magSq[absBin];
Real binEnergy = magSqFromRawFFT(absBin);
if (binEnergy <= rawNoiseFloor * 1.2f) {
continue;
@@ -797,18 +891,10 @@ Real FreqScannerSink::voiceActivityLevel(qint64 freq, int bin, int channelBins,
formantIndexScore = std::max(0.4f, 0.25f + 0.75f * (0.40f * f1IndexScore + 0.40f * f2IndexScore + 0.20f * gapScore));
}
score *= pitchScore * harmonicAlignmentScore * formantIndexScore;
score *= tonalPenalty * pitchScore * harmonicAlignmentScore * formantIndexScore;
// Clamp to [0, 1]
score = std::max(0.0f, std::min(score, 1.0f));
// if (score > m_settings.m_voiceSquelchThreshold) {
// qDebug() << "FreqScannerSink::voiceActivityLevel:"
// << "freq:" << freq + (isLSB ? 1500 : -1500) << "Hz"
// << "harmonicAlignment:" << harmonicAlignmentScore
// << "score:" << score;
// }
return score;
}
plugins/channelrx/freqscanner/freqscannersink.h
+1 -1
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@@ -90,7 +90,7 @@ private:
Real peakPower(int bin, int channelBins) const;
Real magSq(int bin) const;
Real magSqFromRawFFT(int bin) const;
Real voiceActivityLevel(qint64 freq, int bin, int channelBins, bool isLSB);
Real voiceActivityLevel(int bin, int channelBins, bool isLSB);
void getFormantEnvelope(int startBin, int endBin, QVector<Real>& envelope, Real *pitchHz = nullptr);
};