mirror of https://github.com/f4exb/sdrangel.git
123 lines
4.2 KiB
C++
123 lines
4.2 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
|
|
// Copyright (C) 2021 Jon Beniston, M7RCE <jon@beniston.com> //
|
|
// Copyright 2006-2021 Free Software Foundation, Inc. //
|
|
// Copyright (C) 2018 Edouard Griffiths, F4EXB //
|
|
// //
|
|
// Based on the Costas Loop from GNU Radio //
|
|
// //
|
|
// This program is free software; you can redistribute it and/or modify //
|
|
// it under the terms of the GNU General Public License as published by //
|
|
// the Free Software Foundation as version 3 of the License, or //
|
|
// (at your option) any later version. //
|
|
// //
|
|
// This program is distributed in the hope that it will be useful, //
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
|
|
// GNU General Public License V3 for more details. //
|
|
// //
|
|
// You should have received a copy of the GNU General Public License //
|
|
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
|
|
///////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#ifndef SDRBASE_DSP_COSTASLOOP_H_
|
|
#define SDRBASE_DSP_COSTASLOOP_H_
|
|
|
|
#include <QDebug>
|
|
|
|
#include "dsp/dsptypes.h"
|
|
#include "export.h"
|
|
|
|
/** Costas Loop for phase and frequency tracking. */
|
|
class SDRBASE_API CostasLoop
|
|
{
|
|
public:
|
|
CostasLoop(float loopBW, unsigned int pskOrder);
|
|
~CostasLoop();
|
|
|
|
void computeCoefficients(float loopBW);
|
|
void setPskOrder(unsigned int pskOrder) { m_pskOrder = pskOrder; }
|
|
void reset();
|
|
void setSampleRate(unsigned int sampleRate);
|
|
void feed(float re, float im);
|
|
const std::complex<float>& getComplex() const { return m_y; }
|
|
float getReal() const { return m_y.real(); }
|
|
float getImag() const { return m_y.imag(); }
|
|
float getFreq() const { return m_freq; }
|
|
float getPhiHat() const { return m_phase; }
|
|
|
|
private:
|
|
|
|
std::complex<float> m_y;
|
|
float m_phase;
|
|
float m_freq;
|
|
float m_error;
|
|
float m_maxFreq;
|
|
float m_minFreq;
|
|
float m_alpha;
|
|
float m_beta;
|
|
unsigned int m_pskOrder;
|
|
|
|
void advanceLoop(float error)
|
|
{
|
|
m_freq = m_freq + m_beta * error;
|
|
m_phase = m_phase + m_freq + m_alpha * error;
|
|
}
|
|
|
|
void phaseWrap()
|
|
{
|
|
const float two_pi = (float)(2.0 * M_PI);
|
|
|
|
while (m_phase > two_pi)
|
|
m_phase -= two_pi;
|
|
while (m_phase < -two_pi)
|
|
m_phase += two_pi;
|
|
}
|
|
|
|
void frequencyLimit()
|
|
{
|
|
if (m_freq > m_maxFreq)
|
|
m_freq = m_maxFreq;
|
|
else if (m_freq < m_minFreq)
|
|
m_freq = m_minFreq;
|
|
}
|
|
|
|
void setMaxFreq(float freq)
|
|
{
|
|
m_maxFreq = freq;
|
|
}
|
|
|
|
void setMinFreq(float freq)
|
|
{
|
|
m_minFreq = freq;
|
|
}
|
|
|
|
float phaseDetector2(std::complex<float> sample) const // for BPSK
|
|
{
|
|
return (sample.real() * sample.imag());
|
|
}
|
|
|
|
float phaseDetector4(std::complex<float> sample) const // for QPSK
|
|
{
|
|
return ((sample.real() > 0.0f ? 1.0f : -1.0f) * sample.imag() -
|
|
(sample.imag() > 0.0f ? 1.0f : -1.0f) * sample.real());
|
|
};
|
|
|
|
float phaseDetector8(std::complex<float> sample) const // for 8PSK
|
|
{
|
|
const float K = (sqrtf(2.0) - 1);
|
|
if (fabsf(sample.real()) >= fabsf(sample.imag()))
|
|
{
|
|
return ((sample.real() > 0.0f ? 1.0f : -1.0f) * sample.imag() -
|
|
(sample.imag() > 0.0f ? 1.0f : -1.0f) * sample.real() * K);
|
|
}
|
|
else
|
|
{
|
|
return ((sample.real() > 0.0f ? 1.0f : -1.0f) * sample.imag() * K -
|
|
(sample.imag() > 0.0f ? 1.0f : -1.0f) * sample.real());
|
|
}
|
|
};
|
|
|
|
};
|
|
|
|
#endif /* SDRBASE_DSP_COSTASLOOP_H_ */
|