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111 lines
4.2 KiB
C++
111 lines
4.2 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2018 F4EXB //
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// written by Edouard Griffiths //
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// //
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// See: http://liquidsdr.org/blog/pll-howto/ //
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// Fixed filter registers saturation //
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// Added order for PSK locking. This brilliant idea actually comes from this //
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// post: https://www.dsprelated.com/showthread/comp.dsp/36356-1.php //
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// //
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// This program is free software; you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation as version 3 of the License, or //
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// //
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// This program is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License V3 for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with this program. If not, see <http://www.gnu.org/licenses/>. //
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///////////////////////////////////////////////////////////////////////////////////
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#ifndef SDRBASE_DSP_PHASELOCKCOMPLEX_H_
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#define SDRBASE_DSP_PHASELOCKCOMPLEX_H_
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#include "dsp/dsptypes.h"
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#include "export.h"
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/** General purpose Phase-locked loop using complex analytic signal input. */
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class SDRBASE_API PhaseLockComplex
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{
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public:
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PhaseLockComplex();
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/** Compute loop filter parameters (active PI design)
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* \param wn PLL bandwidth relative to Nyquist frequency
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* \param zeta PLL damping factor
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* \param K PLL loop gain
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* */
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void computeCoefficients(Real wn, Real zeta, Real K);
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/** Set the PSK order for the phase comparator
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* \param order 0,1: no PSK (CW), 2: BPSK, 4: QPSK, 8: 8-PSK, ... use powers of two for real cases
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*/
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void setPskOrder(unsigned int order);
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/** Set sample rate information only for frequency and lock condition calculation */
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void setSampleRate(unsigned int sampleRate);
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void reset();
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/** Feed PLL with a new signa sample */
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void feed(float re, float im);
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const std::complex<float>& getComplex() const { return m_y; }
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float getReal() const { return m_yRe; }
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float getImag() const { return m_yIm; }
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bool locked() const { return m_pskOrder > 1 ? m_lockCount > 10 : m_lockCount > m_lockTime-2; }
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float getFreq() const { return m_freq; }
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float getDeltaPhi() const { return m_deltaPhi; }
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float getPhiHat() const { return m_phiHat; }
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private:
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class ExpAvg
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{
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public:
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ExpAvg() : m_a0(0.999), m_a1(0.001), m_y1(0.0f)
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{}
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void setAlpha(const float& alpha)
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{
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m_a0 = alpha;
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m_a1 = 1.0 - alpha;
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}
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float feed(const float& x)
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{
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float y = m_a1*x + m_a0*m_y1;
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m_y1 = y;
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return y;
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}
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private:
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float m_a0; //!< alpha
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float m_a1; //!< 1 - alpha
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float m_y1;
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};
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/** Normalize angle in radians into the [-pi,+pi] region */
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static float normalizeAngle(float angle);
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// a0 = 1 is implied
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float m_a1;
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float m_a2;
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float m_b0;
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float m_b1;
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float m_b2;
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float m_v0;
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float m_v1;
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float m_v2;
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float m_deltaPhi;
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float m_phiHat;
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float m_phiHatPrev;
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std::complex<float> m_y;
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std::complex<float> m_p;
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float m_yRe;
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float m_yIm;
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float m_freq;
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float m_freqPrev;
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float m_freqTest;
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int m_lockCount;
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float m_lockFreq;
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unsigned int m_pskOrder;
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int m_lockTime;
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int m_lockTimeCount;
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ExpAvg m_expAvg;
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};
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#endif /* SDRBASE_DSP_PHASELOCKCOMPLEX_H_ */
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