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LoRa modulator: added extra bandwidth and DE bits - small enhancements

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This commit is contained in:
f4exb
2020-02-11 08:43:02 +01:00
parent 315b8b68c1
commit a5dc668376
5 changed files with 51 additions and 18 deletions
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plugins/channeltx/modlora/loramodsource.cpp
+45 -14
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@@ -35,6 +35,7 @@ LoRaModSource::LoRaModSource() :
m_magsq = 0.0;
initSF(m_settings.m_spreadFactor);
initTest(m_settings.m_spreadFactor, m_settings.m_deBits);
reset();
applySettings(m_settings, true);
applyChannelSettings(m_channelSampleRate, m_channelFrequencyOffset, true);
@@ -61,13 +62,6 @@ void LoRaModSource::initSF(unsigned int sf)
m_quarterSamples = (m_fftLength/4)*LoRaModSettings::oversampling;
m_downChirps = new Complex[2*m_fftLength*LoRaModSettings::oversampling]; // Each table is 2 chirps long to allow use from arbitrary offsets.
m_upChirps = new Complex[2*m_fftLength*LoRaModSettings::oversampling];
m_symbols.clear();
for (unsigned int symbol = m_fftLength/4; symbol < m_fftLength; symbol += m_fftLength/4)
{
m_symbols.push_back(symbol);
m_symbols.push_back(symbol+1);
}
float halfAngle = M_PI/LoRaModSettings::oversampling;
float phase = -halfAngle;
@@ -89,11 +83,32 @@ void LoRaModSource::initSF(unsigned int sf)
m_phaseIncrements = new double[2*m_fftLength*LoRaModSettings::oversampling];
phase = -halfAngle;
for (int i = 0; i < 2*m_fftLength*LoRaModSettings::oversampling; i++)
for (int i = 0; i < m_fftLength*LoRaModSettings::oversampling; i++)
{
m_phaseIncrements[i] = phase;
phase += (2*halfAngle) / (m_fftLength*LoRaModSettings::oversampling);
phase = phase > halfAngle ? -halfAngle : phase;
}
std::copy(
m_phaseIncrements,
m_phaseIncrements+m_fftLength*LoRaModSettings::oversampling,
m_phaseIncrements+m_fftLength*LoRaModSettings::oversampling
);
}
void LoRaModSource::initTest(unsigned int sf, unsigned int deBits)
{
unsigned int fftLength = 1<<sf;
unsigned int symbolRange = fftLength/(1<<deBits);
m_symbols.clear();
for (unsigned int seq = 0; seq < 1; seq++)
{
for (unsigned int symbol = 0; symbol < symbolRange; symbol += symbolRange/4)
{
m_symbols.push_back(symbol);
m_symbols.push_back(symbol+1);
}
}
}
@@ -225,8 +240,9 @@ void LoRaModSource::modulateSample()
else if (m_state == LoRaStateSFD)
{
// m_modSample = m_downChirps[m_chirp];
m_modSample = Complex(std::conj(std::polar(0.891235351562 * SDR_TX_SCALED, m_modPhasor)));
m_modPhasor += m_phaseIncrements[m_chirp];
m_modSample = Complex(std::polar(0.891235351562 * SDR_TX_SCALED, m_modPhasor));
int chirpIndex = m_fftLength*LoRaModSettings::oversampling - 1 - m_chirp;
m_modPhasor += m_phaseIncrements[chirpIndex];
m_fftCounter++;
m_sampleCounter++;
@@ -247,7 +263,7 @@ void LoRaModSource::modulateSample()
{
m_fftCounter = 0;
m_chirpCount = 0;
m_chirp0 = m_symbols[m_chirpCount];
m_chirp0 = encodeSymbol(m_symbols[m_chirpCount]);
m_chirp = (m_chirp0 + m_fftLength)*LoRaModSettings::oversampling - 1;
m_state = LoRaStatePayload;
}
@@ -270,7 +286,7 @@ void LoRaModSource::modulateSample()
}
else
{
m_chirp0 = m_symbols[m_chirpCount];
m_chirp0 = encodeSymbol(m_symbols[m_chirpCount]);
m_chirp = (m_chirp0 + m_fftLength)*LoRaModSettings::oversampling - 1;
m_fftCounter = 0;
}
@@ -289,6 +305,18 @@ void LoRaModSource::modulateSample()
}
}
unsigned int LoRaModSource::encodeSymbol(unsigned int symbol)
{
if (m_settings.m_deBits == 0) {
return symbol;
}
unsigned int deWidth = 1<<m_settings.m_deBits;
unsigned int baseSymbol = symbol % (m_fftLength/deWidth); // symbols range control
return deWidth*baseSymbol;
// return deWidth*baseSymbol + (deWidth/2) - 1;
}
void LoRaModSource::processOneSample(Complex& ci)
{
}
@@ -313,9 +341,12 @@ void LoRaModSource::calculateLevel(Real& sample)
void LoRaModSource::applySettings(const LoRaModSettings& settings, bool force)
{
if ((settings.m_spreadFactor != m_settings.m_spreadFactor) || force)
if ((settings.m_spreadFactor != m_settings.m_spreadFactor)
|| (settings.m_deBits != m_settings.m_deBits)
|| (settings.m_preambleChirps != m_settings.m_preambleChirps)|| force)
{
initSF(settings.m_spreadFactor);
initTest(settings.m_spreadFactor, settings.m_deBits);
reset();
}