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Series of shifted decimators matching shifted interpolators. Applied to HackRF input

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This commit is contained in:
f4exb
2019-04-02 01:10:03 +02:00
parent 6db002bbe3
commit e2ac286458
15 changed files with 2123 additions and 38 deletions
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sdrbase/dsp/devicesamplesource.cpp
+55 -16
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@@ -47,6 +47,7 @@ qint64 DeviceSampleSource::calculateDeviceCenterFrequency(
int log2Decim,
fcPos_t fcPos,
quint32 devSampleRate,
FrequencyShiftScheme frequencyShiftScheme,
bool transverterMode)
{
qint64 deviceCenterFrequency = centerFrequency;
@@ -54,10 +55,11 @@ qint64 DeviceSampleSource::calculateDeviceCenterFrequency(
deviceCenterFrequency = deviceCenterFrequency < 0 ? 0 : deviceCenterFrequency;
qint64 f_img = deviceCenterFrequency;
deviceCenterFrequency -= calculateFrequencyShift(log2Decim, fcPos, devSampleRate);
f_img -= 2*calculateFrequencyShift(log2Decim, fcPos, devSampleRate);
deviceCenterFrequency -= calculateFrequencyShift(log2Decim, fcPos, devSampleRate, frequencyShiftScheme);
f_img -= 2*calculateFrequencyShift(log2Decim, fcPos, devSampleRate, frequencyShiftScheme);
qDebug() << "DeviceSampleSource::calculateDeviceCenterFrequency:"
<< " frequencyShiftScheme: " << frequencyShiftScheme
<< " desired center freq: " << centerFrequency << " Hz"
<< " device center freq: " << deviceCenterFrequency << " Hz"
<< " device sample rate: " << devSampleRate << "S/s"
@@ -74,14 +76,16 @@ qint64 DeviceSampleSource::calculateCenterFrequency(
int log2Decim,
fcPos_t fcPos,
quint32 devSampleRate,
FrequencyShiftScheme frequencyShiftScheme,
bool transverterMode)
{
qint64 centerFrequency = deviceCenterFrequency;
centerFrequency += calculateFrequencyShift(log2Decim, fcPos, devSampleRate);
centerFrequency += calculateFrequencyShift(log2Decim, fcPos, devSampleRate, frequencyShiftScheme);
centerFrequency += transverterMode ? transverterDeltaFrequency : 0;
centerFrequency = centerFrequency < 0 ? 0 : centerFrequency;
qDebug() << "DeviceSampleSource::calculateCenterFrequency:"
<< " frequencyShiftScheme: " << frequencyShiftScheme
<< " desired center freq: " << centerFrequency << " Hz"
<< " device center freq: " << deviceCenterFrequency << " Hz"
<< " device sample rate: " << devSampleRate << "S/s"
@@ -109,25 +113,60 @@ qint64 DeviceSampleSource::calculateCenterFrequency(
qint32 DeviceSampleSource::calculateFrequencyShift(
int log2Decim,
fcPos_t fcPos,
quint32 devSampleRate)
quint32 devSampleRate,
FrequencyShiftScheme frequencyShiftScheme)
{
if (log2Decim == 0) { // no shift at all
return 0;
} else if (log2Decim < 3) {
if (fcPos == FC_POS_INFRA) { // shift in the square next to center frequency
return -(devSampleRate / (1<<(log2Decim+1)));
} else if (fcPos == FC_POS_SUPRA) {
return devSampleRate / (1<<(log2Decim+1));
if (frequencyShiftScheme == FSHIFT_STD)
{
if (log2Decim == 0) { // no shift at all
return 0;
} else if (log2Decim < 3) {
if (fcPos == FC_POS_INFRA) { // shift in the square next to center frequency
return -(devSampleRate / (1<<(log2Decim+1)));
} else if (fcPos == FC_POS_SUPRA) {
return devSampleRate / (1<<(log2Decim+1));
} else {
return 0;
}
} else {
if (fcPos == FC_POS_INFRA) { // shift centered in the square next to center frequency
return -(devSampleRate / (1<<(log2Decim)));
} else if (fcPos == FC_POS_SUPRA) {
return devSampleRate / (1<<(log2Decim));
} else {
return 0;
}
}
}
else if (frequencyShiftScheme == FSHIFT_TXSYNC)
{
if (fcPos == FC_POS_CENTER) {
return 0;
}
} else {
if (fcPos == FC_POS_INFRA) { // shift centered in the square next to center frequency
return -(devSampleRate / (1<<(log2Decim)));
} else if (fcPos == FC_POS_SUPRA) {
return devSampleRate / (1<<(log2Decim));
int sign = fcPos == FC_POS_INFRA ? -1 : 1;
int halfSampleRate = devSampleRate / 2; // fractions are relative to sideband thus based on half the sample rate
if (log2Decim == 0) {
return 0;
} else if (log2Decim == 1) {
return sign * (halfSampleRate / 2); // inf or sup: 1/2
} else if (log2Decim == 2) {
return sign * ((halfSampleRate * 3) / 4); // inf, inf or sup, sup: 1/2 + 1/4
} else if (log2Decim == 3) {
return sign * ((halfSampleRate * 5) / 8); // inf, inf, sup or sup, sup, inf: 1/2 + 1/4 - 1/8 = 5/8
} else if (log2Decim == 4) {
return sign * ((halfSampleRate * 11) / 16); // inf, inf, sup, inf or sup, sup, inf, sup: 1/2 + 1/4 - 1/8 + 1/16 = 11/16
} else if (log2Decim == 5) {
return sign * ((halfSampleRate * 21) / 32); // inf, inf, sup, inf, sup or sup, sup, inf, sup, inf: 1/2 + 1/4 - 1/8 + 1/16 - 1/32 = 21/32
} else if (log2Decim == 6) {
return sign * ((halfSampleRate * 21) / 64); // 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
} else {
return 0;
}
}
else
{
return 0;
}
}