diff --git a/sdrbase/CMakeLists.txt b/sdrbase/CMakeLists.txt
index 0459c898c..ba63ce3e4 100644
--- a/sdrbase/CMakeLists.txt
+++ b/sdrbase/CMakeLists.txt
@@ -34,6 +34,7 @@ set(sdrbase_SOURCES
dsp/filterrc.cpp
dsp/filtermbe.cpp
dsp/filerecord.cpp
+ dsp/freqlockcomplex.cpp
dsp/interpolator.cpp
dsp/hbfiltertraits.cpp
dsp/lowpass.cpp
@@ -124,6 +125,7 @@ set(sdrbase_HEADERS
dsp/filterrc.h
dsp/filtermbe.h
dsp/filerecord.h
+ dsp/freqlockcomplex.h
dsp/gfft.h
dsp/iirfilter.h
dsp/interpolator.h
@@ -271,6 +273,7 @@ include_directories(
.
${CMAKE_SOURCE_DIR}/exports
${CMAKE_SOURCE_DIR}/httpserver
+ ${CMAKE_SOURCE_DIR}/kitiirfir
${CMAKE_SOURCE_DIR}/qrtplib
${CMAKE_SOURCE_DIR}/swagger/sdrangel/code/qt5/client
)
@@ -278,6 +281,7 @@ include_directories(
target_link_libraries(sdrbase
${QT_LIBRARIES}
httpserver
+ kitiirfir
qrtplib
swagger
)
diff --git a/sdrbase/dsp/freqlockcomplex.cpp b/sdrbase/dsp/freqlockcomplex.cpp
new file mode 100644
index 000000000..d0d4a5772
--- /dev/null
+++ b/sdrbase/dsp/freqlockcomplex.cpp
@@ -0,0 +1,122 @@
+///////////////////////////////////////////////////////////////////////////////////
+// Copyright (C) 2018 F4EXB //
+// written by Edouard Griffiths //
+// //
+// See: http://liquidsdr.org/blog/pll-howto/ //
+// Fixed filter registers saturation //
+// Added order for PSK locking. This brilliant idea actually comes from this //
+// post: https://www.dsprelated.com/showthread/comp.dsp/36356-1.php //
+// //
+// 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 //
+// //
+// 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 . //
+///////////////////////////////////////////////////////////////////////////////////
+
+#include "freqlockcomplex.h"
+#include "IIRFilterCode.h"
+
+FreqLockComplex::FreqLockComplex() :
+ m_a0(1.0),
+ m_a1(1.0),
+ m_a2(1.0),
+ m_b0(1.0),
+ m_b1(1.0),
+ m_b2(1.0),
+ m_v0(0.0),
+ m_v1(0.0),
+ m_v2(0.0),
+ m_y(1.0, 0.0),
+ m_prod(1.0, 0.0),
+ m_yRe(1.0),
+ m_yIm(0.0),
+ m_freq(0.0),
+ m_phi(0.0),
+ m_iir(0)
+{
+}
+
+FreqLockComplex::~FreqLockComplex()
+{
+ if (m_iir) {
+ delete m_iir;
+ }
+}
+
+void FreqLockComplex::reset()
+{
+ m_v0 = 0.0f;
+ m_v1 = 0.0f;
+ m_v2 = 0.0f;
+ m_y.real(1.0);
+ m_y.imag(0.0);
+ m_prod.real(1.0);
+ m_prod.imag(0.0);
+ m_yRe = 1.0f;
+ m_yIm = 0.0f;
+ m_freq = 0.0f;
+ m_phi = 0.0f;
+}
+
+// wn is in terms of Nyquist. For example, if the sampling frequency = 20 kHz
+// and the 3 dB corner frequency is 1.5 kHz, then OmegaC = 0.15
+// i.e. 100.0 / (SR/2) or 200 / SR for 100 Hz
+void FreqLockComplex::computeCoefficients(float wn)
+{
+ kitiirfir::TIIRFilterParams params;
+
+ params.BW = 0.0; // For band pass and notch filters - unused here
+ params.Gamma = 0.0; // For Adjustable Gauss. - unused here
+ params.IIRPassType = kitiirfir::iirLPF;
+ params.NumPoles = 1;
+ params.OmegaC = wn;
+ params.ProtoType = kitiirfir::BUTTERWORTH;
+ params.Ripple = 0.0; // For Elliptic and Chebyshev - unused here
+ params.StopBanddB = 0.0; // For Elliptic and Inverse Chebyshev - unused here
+ params.dBGain = 0.0;
+
+ kitiirfir::TIIRCoeff coeff = kitiirfir::CalcIIRFilterCoeff(params);
+ float a[3], b[3];
+
+ a[0] = coeff.a0[0];
+ a[1] = coeff.a1[0];
+ a[2] = coeff.a2[0];
+ b[0] = coeff.b0[0];
+ b[1] = coeff.b1[0];
+ b[2] = coeff.b2[0];
+
+ qDebug("FreqLockComplex::computeCoefficients: b: %f %f %f", b[0], b[1], b[2]);
+ qDebug("FreqLockComplex::computeCoefficients: a: %f %f %f", a[0], a[1], a[2]);
+
+ m_iir = new IIRFilter(a, b);
+}
+
+void FreqLockComplex::feed(float re, float im)
+{
+ m_yRe = cos(m_phi);
+ m_yIm = sin(m_phi);
+ std::complex y(m_yRe, m_yIm);
+ std::complex x(re, im);
+
+ std::complex prod = x * m_y;
+
+ // Discriminator: cross * sign(dot) / dt
+ float cross = m_prod.real()*prod.imag() - prod.real()*m_prod.imag();
+ float dot = m_prod.real()*prod.real() + m_prod.imag()*prod.imag();
+ float eF = cross * (dot < 0 ? -1 : 1); // frequency error
+
+ // LPF section
+ float efHat = m_iir->run(eF);
+
+ m_freq = efHat; // correct instantaneous frequency
+ m_phi += efHat; // advance phase with instantaneous frequency
+ m_prod = prod; // store previous product
+}
+
diff --git a/sdrbase/dsp/freqlockcomplex.h b/sdrbase/dsp/freqlockcomplex.h
new file mode 100644
index 000000000..e860821d0
--- /dev/null
+++ b/sdrbase/dsp/freqlockcomplex.h
@@ -0,0 +1,62 @@
+///////////////////////////////////////////////////////////////////////////////////
+// Copyright (C) 2018 F4EXB //
+// written by Edouard Griffiths //
+// //
+// See: http://liquidsdr.org/blog/pll-howto/ //
+// Fixed filter registers saturation //
+// Added order for PSK locking. This brilliant idea actually comes from this //
+// post: https://www.dsprelated.com/showthread/comp.dsp/36356-1.php //
+// //
+// 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 //
+// //
+// 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 . //
+///////////////////////////////////////////////////////////////////////////////////
+
+#ifndef SDRBASE_DSP_FREQLOCKCOMPLEX_H_
+#define SDRBASE_DSP_FREQLOCKCOMPLEX_H_
+
+#include "dsp/dsptypes.h"
+#include "iirfilter.h"
+#include "export.h"
+
+/** General purpose Phase-locked loop using complex analytic signal input. */
+class SDRBASE_API FreqLockComplex
+{
+public:
+ FreqLockComplex();
+ ~FreqLockComplex();
+
+ void reset();
+ void computeCoefficients(float wn);
+ /** Feed PLL with a new signa sample */
+ void feed(float re, float im);
+
+private:
+ float m_a0;
+ float m_a1;
+ float m_a2;
+ float m_b0;
+ float m_b1;
+ float m_b2;
+ float m_v0;
+ float m_v1;
+ float m_v2;
+ std::complex m_y;
+ std::complex m_prod;
+ float m_yRe;
+ float m_yIm;
+ float m_freq;
+ float m_phi;
+ IIRFilter *m_iir;
+};
+
+
+#endif /* SDRBASE_DSP_FREQLOCKCOMPLEX_H_ */