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HackRF output: compensate shifted interpolators

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This commit is contained in:
f4exb 2019-04-01 14:40:01 +02:00
parent bfcfe8f87c
commit dc4a98b58a
3 changed files with 41 additions and 30 deletions
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11
plugins/samplesink/hackrfoutput/hackrfoutput.cpp
View File

@ -278,7 +278,7 @@ bool HackRFOutput::handleMessage(const Message& message)
freqMsg.getFrequency(), freqMsg.getFrequency(),
0, 0,
m_settings.m_log2Interp, m_settings.m_log2Interp,
DeviceSampleSink::FC_POS_CENTER, (DeviceSampleSink::fcPos_t) m_settings.m_fcPos,
m_settings.m_devSampleRate); m_settings.m_devSampleRate);
qDebug("HackRFOutput::handleMessage: MsgSynchronizeFrequency: centerFrequency: %lld Hz", centerFrequency); qDebug("HackRFOutput::handleMessage: MsgSynchronizeFrequency: centerFrequency: %lld Hz", centerFrequency);
HackRFOutputSettings settings = m_settings; HackRFOutputSettings settings = m_settings;
@ -414,14 +414,17 @@ bool HackRFOutput::applySettings(const HackRFOutputSettings& settings, bool forc
reverseAPIKeys.append("LOppmTenths"); reverseAPIKeys.append("LOppmTenths");
} }
if (force || (m_settings.m_centerFrequency != settings.m_centerFrequency) || if ((m_settings.m_centerFrequency != settings.m_centerFrequency) ||
(m_settings.m_LOppmTenths != settings.m_LOppmTenths)) (m_settings.m_devSampleRate != settings.m_devSampleRate) ||
(m_settings.m_LOppmTenths != settings.m_LOppmTenths) ||
(m_settings.m_log2Interp != settings.m_log2Interp) ||
(m_settings.m_fcPos != settings.m_fcPos) || force)
{ {
qint64 deviceCenterFrequency = DeviceSampleSink::calculateDeviceCenterFrequency( qint64 deviceCenterFrequency = DeviceSampleSink::calculateDeviceCenterFrequency(
settings.m_centerFrequency, settings.m_centerFrequency,
0, 0,
settings.m_log2Interp, settings.m_log2Interp,
DeviceSampleSink::FC_POS_CENTER, (DeviceSampleSink::fcPos_t) settings.m_fcPos,
settings.m_devSampleRate); settings.m_devSampleRate);
setDeviceCenterFrequency(deviceCenterFrequency, settings.m_LOppmTenths); setDeviceCenterFrequency(deviceCenterFrequency, settings.m_LOppmTenths);

1
plugins/samplesink/hackrfoutput/hackrfoutputgui.cpp
View File

@ -211,6 +211,7 @@ void HackRFOutputGui::displaySettings()
ui->sampleRate->setValue(m_settings.m_devSampleRate); ui->sampleRate->setValue(m_settings.m_devSampleRate);
ui->interp->setCurrentIndex(m_settings.m_log2Interp); ui->interp->setCurrentIndex(m_settings.m_log2Interp);
ui->fcPos->setCurrentIndex((int) m_settings.m_fcPos);
ui->lnaExt->setChecked(m_settings.m_lnaExt); ui->lnaExt->setChecked(m_settings.m_lnaExt);
ui->txvgaGainText->setText(tr("%1dB").arg(m_settings.m_vgaGain)); ui->txvgaGainText->setText(tr("%1dB").arg(m_settings.m_vgaGain));

55
sdrbase/dsp/devicesamplesink.cpp
View File

@ -96,41 +96,48 @@ qint64 DeviceSampleSink::calculateCenterFrequency(
/** /**
* log2Interp = 0: no shift * log2Interp = 0: no shift
* *
* n = log2Interp <= 2: fc = +/- 1/2^(n-1) * log2Interp = 1: middle of side band (inf or sup: 1/2)
* center * ^ | ^
* | ^ | * | inf | inf | sup | sup |
* | inf | sup | *
* ^ ^ * log2Interp = 2: middle of far side half side band (inf, inf or sup, sup: 1/2 + 1/4)
* ^ | ^
* | inf | inf | sup | sup |
*
* log2Interp = 3: inf, inf, sup or sup, sup, inf: 1/2 + 1/4 - 1/8 = 5/8
* log2Interp = 4: inf, inf, sup, inf or sup, sup, inf, sup: 1/2 + 1/4 - 1/8 + 1/16 = 11/16
* log2Interp = 5: inf, inf, sup, inf, sup or sup, sup, inf, sup, inf: 1/2 + 1/4 - 1/8 + 1/16 - 1/32 = 21/32
* log2Interp = 6: inf, sup, inf, sup, inf, sup or sup, inf, sup, inf, sup, inf: 1/2 - 1/4 + 1/8 -1/16 + 1/32 - 1/64 = 21/64
* *
* n = log2Interp > 2: fc = +/- 1/2^n
* center
* | ^ |
* | |inf| | |sup| |
* ^ ^
*/ */
qint32 DeviceSampleSink::calculateFrequencyShift( qint32 DeviceSampleSink::calculateFrequencyShift(
int log2Interp, int log2Interp,
fcPos_t fcPos, fcPos_t fcPos,
quint32 devSampleRate) quint32 devSampleRate)
{ {
if (log2Interp == 0) { // no shift at all if (fcPos == FC_POS_CENTER) {
return 0;
} else if (log2Interp < 3) {
if (fcPos == FC_POS_INFRA) { // shift in the square next to center frequency
return -(devSampleRate / (1<<(log2Interp+1)));
} else if (fcPos == FC_POS_SUPRA) {
return devSampleRate / (1<<(log2Interp+1));
} else {
return 0; return 0;
} }
} else {
if (fcPos == FC_POS_INFRA) { // shift centered in the square next to center frequency int sign = fcPos == FC_POS_INFRA ? -1 : 1;
return -(devSampleRate / (1<<(log2Interp))); int halfSampleRate = devSampleRate / 2; // fractions are relative to sideband thus based on half the sample rate
} else if (fcPos == FC_POS_SUPRA) {
return devSampleRate / (1<<(log2Interp)); if (log2Interp == 0) {
return 0;
} else if (log2Interp == 1) {
return sign * (halfSampleRate / 2);
} else if (log2Interp == 2) {
return sign * ((halfSampleRate * 3) / 4);
} else if (log2Interp == 3) {
return sign * ((halfSampleRate * 5) / 8);
} else if (log2Interp == 4) {
return sign * ((halfSampleRate * 11) / 16);
} else if (log2Interp == 5) {
return sign * ((halfSampleRate * 21) / 32);
} else if (log2Interp == 6) {
return sign * ((halfSampleRate * 21) / 64);
} else { } else {
return 0; return 0;
} }
}
} }