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New PLL: heuristics to find locked state

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This commit is contained in:
f4exb
2018-05-16 01:57:16 +02:00
parent bb2d530122
commit 660d8d22ae
6 changed files with 379 additions and 337 deletions
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sdrbase/dsp/phaselockcomplex.cpp
+66 -21
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@@ -44,9 +44,14 @@ PhaseLockComplex::PhaseLockComplex() :
m_yRe(1.0),
m_yIm(0.0),
m_freq(0.0),
m_freqPrev(0.0),
m_lock(0.0),
m_lockCount(0),
m_pskOrder(1)
m_pskOrder(1),
m_lockTime1(480),
m_lockTime(2400),
m_lockTimef(2400.0f),
m_lockThreshold(4.8f)
{
}
@@ -83,6 +88,16 @@ void PhaseLockComplex::computeCoefficients(Real wn, Real zeta, Real K)
void PhaseLockComplex::setPskOrder(unsigned int order)
{
m_pskOrder = order > 0 ? order : 1;
reset();
}
void PhaseLockComplex::setSampleRate(unsigned int sampleRate)
{
m_lockTime1 = sampleRate / 100; // 10ms for order 1
m_lockTime = sampleRate / 20; // 50ms for order > 1
m_lockTimef = (float) m_lockTime;
m_lockThreshold = m_lockTime * 0.002f; // threshold of 0.002 taking division by lock time into account
reset();
}
void PhaseLockComplex::reset()
@@ -103,6 +118,7 @@ void PhaseLockComplex::reset()
m_yRe = 1.0f;
m_yIm = 0.0f;
m_freq = 0.0f;
m_freqPrev = 0.0f;
m_lock = 0.0f;
m_lockCount = 0;
}
@@ -148,40 +164,69 @@ void PhaseLockComplex::feed(float re, float im)
m_phiHat += 2.0*M_PI;
}
float dPhi = normalizeAngle(m_phiHat - m_phiHatPrev);
m_phiHatPrev = m_phiHat;
if (m_phiHatCount < 9)
// lock estimation
if (m_pskOrder > 1)
{
m_dPhiHatAccum += dPhi;
float dPhi = normalizeAngle(m_phiHat - m_phiHatPrev);
if (m_phiHatCount < (m_lockTime-1))
{
m_dPhiHatAccum += dPhi; // re-accumulate phase for differential calculation
m_phiHatCount++;
}
else
{
float dPhi11 = (m_dPhiHatAccum - m_phiHat1); // optimized out division by lock time
float dPhi12 = (m_phiHat1 - m_phiHat2);
m_lock = dPhi11 - dPhi12; // second derivative of phase to get lock status
if ((m_lock > -m_lockThreshold) && (m_lock < m_lockThreshold)) // includes re-multiplication by lock time
{
if (m_lockCount < 20) { // [0..20]
m_lockCount++;
}
}
else
{
if (m_lockCount > 0) {
m_lockCount -= 2;
}
}
m_phiHat2 = m_phiHat1;
m_phiHat1 = m_dPhiHatAccum;
m_dPhiHatAccum = 0.0f;
m_phiHatCount = 0;
}
m_phiHatPrev = m_phiHat;
}
else
{
float dPhi1 = (m_phiHat1 - m_dPhiHatAccum) / 10.0f;
float dPhi1Prev = (m_phiHat2 - m_phiHat1) / 10.0f;
m_lock = dPhi1 - dPhi1Prev; // second derivative of phase
m_freq = (m_phiHat - m_phiHatPrev) / (2.0*M_PI);
if ((m_lock > -0.01) && (m_lock < 0.01))
if (m_freq < -1.0f) {
m_freq += 2.0f;
} else if (m_freq > 1.0f) {
m_freq -= 2.0f;
}
float dFreq = m_freq - m_freqPrev;
if ((dFreq > -0.01) && (dFreq < 0.01))
{
if (m_lockCount < 1000) {
if (m_lockCount < (m_lockTime1-1)) { // [0..479]
m_lockCount++;
}
}
else
{
if (m_lockCount > 0) {
m_lockCount--;
}
m_lockCount = 0;
}
m_freq = dPhi1 / 2.0*M_PI; // first derivative of phase
m_phiHat2 = m_phiHat1;
m_phiHat1 = m_dPhiHatAccum;
m_dPhiHatAccum = 0.0f;
m_phiHatCount = 0;
m_phiHatPrev = m_phiHat;
m_freqPrev = m_freq;
}
m_dPhiHatAccum += dPhi;
}
float PhaseLockComplex::normalizeAngle(float angle)