added a OQPSK demodulator

grc/CMakeLists.txt

@@ -22,5 +22,6 @@ install(FILES
     digitalhf_physical_layer_driver.xml
     digitalhf_doppler_correction_cc.xml
     digitalhf_cis_12_channelizer.xml
+    digitalhf_oqpsk_demodulator.xml
     digitalhf_msg_proxy.xml DESTINATION share/gnuradio/grc/blocks
 )

grc/digitalhf_oqpsk_demodulator.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0"?>
+<block>
+  <name>oqpsk_demodulator</name>
+  <key>digitalhf_oqpsk_demodulator</key>
+  <category>[digitalhf]</category>
+  <import>import digitalhf</import>
+  <make>digitalhf.oqpsk_demodulator($fs, $fd, $loop_bw, $df)</make>
+  <param>
+    <name>fs (Hz)</name>
+    <key>fs</key>
+    <type>float</type>
+  </param>
+  <param>
+    <name>fd (Hz)</name>
+    <key>fd</key>
+    <type>float</type>
+  </param>
+  <param>
+    <name>loop_bw</name>
+    <key>loop_bw</key>
+    <type>float</type>
+  </param>
+  <param>
+    <name>df (Hz)</name>
+    <key>df</key>
+    <type>float</type>
+  </param>
+  <sink>
+    <name>in</name>
+    <type>complex</type>
+  </sink>
+  <source>
+    <name>soft_dec_x</name>
+    <type>float</type>
+  </source>
+  <source>
+    <name>soft_dec_y</name>
+    <type>float</type>
+  </source>
+</block>

include/digitalhf/CMakeLists.txt

@@ -29,6 +29,7 @@ install(FILES
     viterbi29.h
     viterbi39.h
     viterbi48.h
+    oqpsk_demodulator.h
     vector_pll_cc.h
     DESTINATION include/digitalhf
 )

include/digitalhf/oqpsk_demodulator.h

@@ -0,0 +1,60 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2019 hcab14@gmail.com.
+ *
+ * This 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; either version 3, or (at your option)
+ * any later version.
+ *
+ * This software 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+
+#ifndef INCLUDED_DIGITALHF_OQPSK_DEMODULATOR_H
+#define INCLUDED_DIGITALHF_OQPSK_DEMODULATOR_H
+
+#include <digitalhf/api.h>
+#include <gnuradio/block.h>
+
+namespace gr {
+namespace digitalhf {
+
+/*!
+ * \brief <+description of block+>
+ * \ingroup digitalhf
+ *
+ */
+class DIGITALHF_API oqpsk_demodulator : virtual public gr::block
+{
+  public:
+  typedef boost::shared_ptr<oqpsk_demodulator> sptr;
+
+  /*!
+   * \brief Return a shared_ptr to a new instance of digitalhf::oqpsk_demodulator.
+   *
+   * To avoid accidental use of raw pointers, digitalhf::oqpsk_demodulator's
+   * constructor is in a private implementation
+   * class. digitalhf::oqpsk_demodulator::make is the public interface for
+   * creating new instances.
+   */
+  static sptr make(float fs=240e3,
+                   float fd=48e3,
+                   float loop_bw=3.1415/100.0f,
+                   float df=20.0f);
+
+};
+
+} // namespace digitalhf
+} // namespace gr
+
+#endif /* INCLUDED_DIGITALHF_OQPSK_DEMODULATOR_H */
+

lib/CMakeLists.txt

@@ -32,6 +32,7 @@ list(APPEND digitalhf_sources
     viterbi29_impl.cc
     viterbi39_impl.cc
     viterbi48_impl.cc
+    oqpsk_demodulator_impl.cc
     vector_pll_cc_impl.cc
     vector_early_late_cc_impl.cc
     lms.cc

lib/oqpsk_demodulator_impl.cc

@@ -0,0 +1,152 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2019 hcab14@gmail.com.
+ *
+ * This 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; either version 3, or (at your option)
+ * any later version.
+ *
+ * This software 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <cmath>
+#include <gnuradio/io_signature.h>
+#include <gnuradio/expj.h>
+#include <gnuradio/logger.h>
+#include <gnuradio/math.h>
+#include <gnuradio/sincos.h>
+
+#include "oqpsk_demodulator_impl.h"
+
+namespace gr {
+namespace digitalhf {
+
+my_control_loop::~my_control_loop() {
+}
+
+void
+my_control_loop::phase_wrap(float x)
+{
+  //  d_phase = fmodf(d_phase, x);
+  while (d_phase > x)
+    d_phase -= x;
+  while (d_phase < -x)
+    d_phase += x;
+}
+
+oqpsk_demodulator::sptr
+oqpsk_demodulator::make(float fs,
+                        float fd,
+                        float loop_bw,
+                        float df)
+{
+  return gnuradio::get_initial_sptr
+    (new oqpsk_demodulator_impl(fs, fd, loop_bw, df));
+}
+
+/*
+ * The private constructor
+ */
+oqpsk_demodulator_impl::oqpsk_demodulator_impl(float fs,
+                                               float fd,
+                                               float loop_bw,
+                                               float df)
+  : gr::block("oqpsk_demodulator",
+              gr::io_signature::make(1, 1, sizeof(gr_complex)),
+              gr::io_signature::make(2, 2, sizeof(float)))
+  , _pll_plus (loop_bw,
+               (+0.5f*fd + df)/fs*2*M_PI,
+               (+0.5f*fd - df)/fs*2*M_PI)
+  , _pll_minus(loop_bw,
+               (-0.5f*fd + df)/fs*2*M_PI,
+               (-0.5f*fd - df)/fs*2*M_PI)
+  , _soft_dec_x(0.0f)
+  , _soft_dec_y(0.0f)
+  , _soft_dec_x_last(0.0f)
+  , _soft_dec_y_last(0.0f)
+  , _code_cos_last(0.0f)
+  , _code_sin_last(0.0f)
+{
+  GR_LOG_DECLARE_LOGPTR(d_logger);
+  GR_LOG_ASSIGN_LOGPTR(d_logger, "oqpsk_demodulator");
+}
+
+oqpsk_demodulator_impl::~oqpsk_demodulator_impl()
+{
+}
+
+int
+oqpsk_demodulator_impl::general_work(int noutput_items,
+                                     gr_vector_int& ninput_items,
+                                     gr_vector_const_void_star &input_items,
+                                     gr_vector_void_star &output_items)
+{
+  gr::thread::scoped_lock lock(d_setlock);
+  gr_complex const* in = static_cast<gr_complex const*>(input_items[0]);
+  float* out_x = static_cast<float*>(output_items[0]);
+  float* out_y = static_cast<float*>(output_items[1]);
+
+  int nout = 0;
+  int i = 0;
+  for (; i<ninput_items[0] && nout < noutput_items; ++i) {
+    gr_complex const sample = *in++;
+
+    float const carr_phase = 0.25f*(_pll_plus.get_phase() + _pll_minus.get_phase());
+    float const code_phase = 0.25f*(_pll_plus.get_phase() - _pll_minus.get_phase());
+
+    float code_sin(0.0f), code_cos(0.0f);
+    gr::sincosf(code_phase, &code_sin, &code_cos);
+
+    if (std::signbit(code_cos) != std::signbit(_code_cos_last)) {
+      _soft_dec_x_last = _soft_dec_x;
+      _soft_dec_x = 0.0f;
+      *out_x++ = _soft_dec_x_last;
+      *out_y++ = _soft_dec_y_last;
+      nout += 1;
+    }
+
+    if (std::signbit(code_sin) != std::signbit(_code_sin_last)) {
+      _soft_dec_y_last = _soft_dec_y;
+      _soft_dec_y = 0.0f;
+      *out_x++ = _soft_dec_x_last;
+      *out_y++ = _soft_dec_y_last;
+      nout += 1;
+    }
+
+    _code_cos_last = code_cos;
+    _code_sin_last = code_sin;
+
+    gr_complex const z = sample*gr_expj(-carr_phase);
+    _soft_dec_x += code_cos * std::real(z);
+    _soft_dec_y += code_sin * std::imag(z);
+
+    gr_complex const z2 = sample*sample;
+    float const error_plus = gr::fast_atan2f(z2 * gr_expj(-_pll_plus.get_phase()));
+    _pll_plus.advance_loop(error_plus);
+    _pll_plus.phase_wrap(8*M_PI);
+    _pll_plus.frequency_limit();
+
+    float const error_minus = gr::fast_atan2f(z2 * gr_expj(-_pll_minus.get_phase()));
+    _pll_minus.advance_loop(error_minus);
+    _pll_minus.phase_wrap(8*M_PI);
+    _pll_minus.frequency_limit();
+  }
+  consume_each(i);
+  return nout;
+}
+
+} /* namespace digitalhf */
+} /* namespace gr */

lib/oqpsk_demodulator_impl.h

@@ -0,0 +1,72 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2019 hcab14@gmail.com.
+ *
+ * This 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; either version 3, or (at your option)
+ * any later version.
+ *
+ * This software 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef INCLUDED_DIGITALHF_OQPSK_DEMODULATOR_IMPL_H
+#define INCLUDED_DIGITALHF_OQPSK_DEMODULATOR_IMPL_H
+
+#include <gnuradio/blocks/control_loop.h>
+
+#include <digitalhf/oqpsk_demodulator.h>
+
+namespace gr {
+namespace digitalhf {
+
+class my_control_loop : public blocks::control_loop {
+public:
+  my_control_loop(float loop_bw, float max_freq, float min_freq)
+    : blocks::control_loop(loop_bw, max_freq, min_freq) {}
+  virtual ~my_control_loop();
+
+  virtual void phase_wrap(float x);
+protected:
+} ;
+
+class oqpsk_demodulator_impl : public oqpsk_demodulator
+{
+private:
+  my_control_loop _pll_plus;
+  my_control_loop _pll_minus;
+
+  float _soft_dec_x;
+  float _soft_dec_y;
+  float _soft_dec_x_last;
+  float _soft_dec_y_last;
+  float _code_cos_last;
+  float _code_sin_last;
+public:
+  oqpsk_demodulator_impl(float fs,
+                         float fd,
+                         float loop_bw,
+                         float df);
+  virtual ~oqpsk_demodulator_impl();
+
+  int general_work(int noutput_items,
+                   gr_vector_int& ninput_items,
+                   gr_vector_const_void_star &input_items,
+                   gr_vector_void_star &output_items);
+
+protected:
+
+};
+
+} // namespace digitalhf
+} // namespace gr
+
+#endif /* INCLUDED_DIGITALHF_OQPSK_DEMODULATOR_IMPL_H */

swig/digitalhf_swig.i

@@ -10,6 +10,7 @@
 %{
 #include "digitalhf/adaptive_dfe.h"
 #include "digitalhf/doppler_correction_cc.h"
+#include "digitalhf/oqpsk_demodulator.h"
 #include "digitalhf/viterbi27.h"
 #include "digitalhf/viterbi29.h"
 #include "digitalhf/viterbi39.h"
@@ -27,6 +28,9 @@ GR_SWIG_BLOCK_MAGIC2(digitalhf, doppler_correction_cc);
 %include "digitalhf/vector_pll_cc.h"
 GR_SWIG_BLOCK_MAGIC2(digitalhf, vector_pll_cc);
 
+%include "digitalhf/oqpsk_demodulator.h"
+GR_SWIG_BLOCK_MAGIC2(digitalhf, oqpsk_demodulator);
+
 %include "digitalhf/vector_early_late_cc.h"
 GR_SWIG_BLOCK_MAGIC2(digitalhf, vector_early_late_cc);