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New PLL: simple FLL code to be put in its own class later

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This commit is contained in:
f4exb 2018-05-16 18:53:16 +02:00
parent a1a2078d7d
commit d38d926a87
2 changed files with 15 additions and 48 deletions
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62
sdrbase/dsp/phaselockcomplex.cpp
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@ -41,6 +41,7 @@ PhaseLockComplex::PhaseLockComplex() :
m_dPhiHatAccum(0.0), m_dPhiHatAccum(0.0),
m_phiHatCount(0), m_phiHatCount(0),
m_y(1.0, 0.0), m_y(1.0, 0.0),
m_p(1.0, 0.0),
m_yRe(1.0), m_yRe(1.0),
m_yIm(0.0), m_yIm(0.0),
m_freq(0.0), m_freq(0.0),
@ -116,7 +117,9 @@ void PhaseLockComplex::reset()
m_dPhiHatAccum = 0.0f; m_dPhiHatAccum = 0.0f;
m_phiHatCount = 0; m_phiHatCount = 0;
m_y.real(1.0); m_y.real(1.0);
m_y.real(0.0); m_y.imag(0.0);
m_p.real(1.0);
m_p.imag(0.0);
m_yRe = 1.0f; m_yRe = 1.0f;
m_yIm = 0.0f; m_yIm = 0.0f;
m_freq = 0.0f; m_freq = 0.0f;
@ -127,40 +130,18 @@ void PhaseLockComplex::reset()
void PhaseLockComplex::feedFLL(float re, float im) void PhaseLockComplex::feedFLL(float re, float im)
{ {
m_yRe = cos(m_phiHat);
m_yIm = sin(m_phiHat);
std::complex<float> y(m_yRe, m_yIm);
std::complex<float> x(re, im); std::complex<float> x(re, im);
m_phiHat1 = std::arg(x); std::complex<float> p = x * m_y;
float dPhi = normalizeAngle(m_phiHat1 - m_phiHat2); // instantanoeus radian valued signal frequency in [-pi..pi] range float cross = m_p.real()*p.imag() - p.real()*m_p.imag();
m_phiHat2 = m_phiHat1; float dot = m_p.real()*p.real() + m_p.imag()*p.imag();
float eF = cross * (dot < 0 ? -1 : 1); // frequency error
// advance buffer m_freq += eF; // correct instantaneous frequency
m_v2 = m_v1; // shift center register to upper register m_phiHat += eF; // advance phase with instantaneous frequency
m_v1 = m_v0; // shift lower register to center register m_p = p; // store previous product
// compute new lower register
m_v0 = dPhi - m_v1*m_a1 - m_v2*m_a2;
// compute new output
float freqHat = m_v0*m_b0 + m_v1*m_b1 + m_v2*m_b2;
// prevent saturation
if (freqHat > 2.0*M_PI)
{
m_v0 *= (freqHat - 2.0*M_PI) / freqHat;
m_v1 *= (freqHat - 2.0*M_PI) / freqHat;
m_v2 *= (freqHat - 2.0*M_PI) / freqHat;
freqHat -= 2.0*M_PI;
}
if (freqHat < -2.0*M_PI)
{
m_v0 *= (freqHat + 2.0*M_PI) / freqHat;
m_v1 *= (freqHat + 2.0*M_PI) / freqHat;
m_v2 *= (freqHat + 2.0*M_PI) / freqHat;
freqHat += 2.0*M_PI;
}
m_phiHat += freqHat; // advance phase estimate with filtered signal frequency
m_freq = freqHat / 2.0*M_PI;
} }
void PhaseLockComplex::feed(float re, float im) void PhaseLockComplex::feed(float re, float im)
@ -236,21 +217,6 @@ void PhaseLockComplex::feed(float re, float im)
m_phiHatCount = 0; m_phiHatCount = 0;
} }
// m_avgPhi(m_phiHat);
// float vPhi = normalizeAngle(m_phiHat - m_avgPhi.asFloat());
//
// if ((vPhi > -0.2) && (vPhi < 0.2)) // locked condition
// {
// if (m_lockCount < 20) { // [0..20]
// m_lockCount++;
// }
// }
// else // unlocked condition
// {
// m_lockCount = 0;
// }
// if (m_phiHatCount < (m_lockTime-1)) // if (m_phiHatCount < (m_lockTime-1))
// { // {
// m_dPhiHatAccum += dPhi; // re-accumulate phase for differential calculation // m_dPhiHatAccum += dPhi; // re-accumulate phase for differential calculation

1
sdrbase/dsp/phaselockcomplex.h
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@ -77,6 +77,7 @@ private:
float m_dPhiHatAccum; float m_dPhiHatAccum;
int m_phiHatCount; int m_phiHatCount;
std::complex<float> m_y; std::complex<float> m_y;
std::complex<float> m_p;
float m_yRe; float m_yRe;
float m_yIm; float m_yIm;
float m_freq; float m_freq;