add modified costas
git-svn-id: http://op25.osmocom.org/svn/trunk@213 65a5c917-d112-43f1-993d-58c26a4786be
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@ -67,6 +67,7 @@ _repeater_la_SOURCES = repeater\
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repeater_ctcss_squelch_ff.cc \
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repeater_squelch_base_ff.cc \
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repeater_gardner_symbol_recovery_cc.cc \
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repeater_costas_loop_cc.cc \
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bch.cc
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# magic flags
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@ -88,6 +89,7 @@ grinclude_HEADERS = \
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repeater_imbe_decode_fb.h \
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repeater_pipe.h \
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repeater_gardner_symbol_recovery_cc.h \
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repeater_costas_loop_cc.h \
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repeater_ctcss_squelch_ff.h
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@ -14,6 +14,7 @@
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#include "repeater_pipe.h"
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#include "repeater_ctcss_squelch_ff.h"
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#include "repeater_gardner_symbol_recovery_cc.h"
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#include "repeater_costas_loop_cc.h"
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#include <stdexcept>
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%}
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@ -126,3 +127,28 @@ class repeater_gardner_symbol_recovery_cc : public gr_sync_block
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private:
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repeater_gardner_symbol_recovery_cc (int samples_per_symbol, float timing_error_gain);
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};
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// ----------------------------------------------------------------
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GR_SWIG_BLOCK_MAGIC(repeater,costas_loop_cc);
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repeater_costas_loop_cc_sptr
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repeater_make_costas_loop_cc (float alpha, float beta,
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float max_freq, float min_freq,
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int order
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) throw (std::invalid_argument);
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class repeater_costas_loop_cc : public gr_sync_block
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{
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private:
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repeater_costas_loop_cc (float alpha, float beta,
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float max_freq, float min_freq, int order);
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public:
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void set_alpha(float alpha);
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float alpha();
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void set_beta(float beta);
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float beta();
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float freq();
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};
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@ -0,0 +1,189 @@
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/* -*- c++ -*- */
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/*
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* Copyright 2006 Free Software Foundation, Inc.
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*
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* PI/4 DQPSK hack Copyright 2010 KA1RBI
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*
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* This file is part of GNU Radio
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*
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* GNU Radio 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; either version 3, or (at your option)
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* any later version.
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*
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* GNU Radio 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 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 GNU Radio; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <repeater_costas_loop_cc.h>
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#include <gr_io_signature.h>
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#include <gr_expj.h>
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#include <gr_sincos.h>
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#include <math.h>
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#define M_TWOPI (2*M_PI)
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static const gr_complex PT_45 = gr_expj( M_PI / 4.0 );
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repeater_costas_loop_cc_sptr
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repeater_make_costas_loop_cc (float alpha, float beta,
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float max_freq, float min_freq,
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int order
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) throw (std::invalid_argument)
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{
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return repeater_costas_loop_cc_sptr (new repeater_costas_loop_cc (alpha, beta,
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max_freq, min_freq,
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order));
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}
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repeater_costas_loop_cc::repeater_costas_loop_cc (float alpha, float beta,
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float max_freq, float min_freq,
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int order
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) throw (std::invalid_argument)
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: gr_sync_block ("costas_loop_cc",
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gr_make_io_signature (1, 1, sizeof (gr_complex)),
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gr_make_io_signature (1, 2, sizeof (gr_complex))),
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d_alpha(alpha), d_beta(beta),
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d_max_freq(max_freq), d_min_freq(min_freq),
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d_phase(0), d_freq((max_freq+min_freq)/2),
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d_order(order), d_phase_detector(0),
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d_interp_counter(0), d_rot45(false)
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{
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if (d_order < 0) {
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d_rot45 = true;
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d_order = 0 - d_order;
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}
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switch(d_order) {
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case 2:
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d_phase_detector = &repeater_costas_loop_cc::phase_detector_2;
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break;
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case 4:
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d_phase_detector = &repeater_costas_loop_cc::phase_detector_4;
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break;
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default:
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throw std::invalid_argument("order must be 2 or 4");
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break;
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}
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}
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float
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repeater_costas_loop_cc::phase_detector_4(gr_complex sample) const
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{
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return ((sample.real()>0 ? 1.0 : -1.0) * sample.imag() -
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(sample.imag()>0 ? 1.0 : -1.0) * sample.real());
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}
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float
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repeater_costas_loop_cc::phase_detector_2(gr_complex sample) const
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{
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return (sample.real()*sample.imag());
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}
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void
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repeater_costas_loop_cc::set_alpha(float alpha)
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{
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d_alpha = alpha;
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}
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void
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repeater_costas_loop_cc::set_beta(float beta)
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{
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d_beta = beta;
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}
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int
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repeater_costas_loop_cc::work (int noutput_items,
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gr_vector_const_void_star &input_items,
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gr_vector_void_star &output_items)
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{
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const gr_complex *iptr = (gr_complex *) input_items[0];
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gr_complex *optr = (gr_complex *) output_items[0];
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gr_complex *foptr = (gr_complex *) output_items[1];
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bool write_foptr = output_items.size() >= 2;
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float error;
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gr_complex nco_out;
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gr_complex rotated_sample;
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if (write_foptr) {
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for (int i = 0; i < noutput_items; i++){
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nco_out = gr_expj(-d_phase);
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rotated_sample = optr[i] = iptr[i] * nco_out;
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if (d_rot45) {
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if (d_interp_counter & 1) // every other symbol
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rotated_sample = rotated_sample * PT_45; // rotate by +45 deg
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d_interp_counter++;
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}
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error = (*this.*d_phase_detector)(rotated_sample);
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if (error > 1)
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error = 1;
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else if (error < -1)
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error = -1;
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d_freq = d_freq + d_beta * error;
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d_phase = d_phase + d_freq + d_alpha * error;
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while(d_phase>M_TWOPI)
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d_phase -= M_TWOPI;
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while(d_phase<-M_TWOPI)
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d_phase += M_TWOPI;
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if (d_freq > d_max_freq)
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d_freq = d_max_freq;
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else if (d_freq < d_min_freq)
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d_freq = d_min_freq;
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foptr[i] = gr_complex(d_freq,0);
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}
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} else {
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for (int i = 0; i < noutput_items; i++){
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nco_out = gr_expj(-d_phase);
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rotated_sample = optr[i] = iptr[i] * nco_out;
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if (d_rot45) {
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if (d_interp_counter & 1) // every other symbol
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rotated_sample = rotated_sample * PT_45; // rotate by +45 deg
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d_interp_counter++;
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}
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error = (*this.*d_phase_detector)(rotated_sample);
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if (error > 1)
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error = 1;
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else if (error < -1)
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error = -1;
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d_freq = d_freq + d_beta * error;
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d_phase = d_phase + d_freq + d_alpha * error;
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while(d_phase>M_TWOPI)
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d_phase -= M_TWOPI;
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while(d_phase<-M_TWOPI)
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d_phase += M_TWOPI;
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if (d_freq > d_max_freq)
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d_freq = d_max_freq;
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else if (d_freq < d_min_freq)
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d_freq = d_min_freq;
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}
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}
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return noutput_items;
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}
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@ -0,0 +1,142 @@
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/* -*- c++ -*- */
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/*
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* Copyright 2006 Free Software Foundation, Inc.
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*
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* This file is part of GNU Radio
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*
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* GNU Radio 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; either version 3, or (at your option)
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* any later version.
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*
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* GNU Radio 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 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 GNU Radio; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef INCLUDED_REPEATER_COSTAS_LOOP_CC_H
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#define INCLUDED_REPEATER_COSTAS_LOOP_CC_H
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#include <gr_sync_block.h>
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#include <stdexcept>
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#include <fstream>
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/*! \brief A Costas loop carrier recovery module.
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* \ingroup sync_blk
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*
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* The Costas loop locks to the center frequency of a signal and
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* downconverts it to baseband. The second (order=2) order loop is
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* used for BPSK where the real part of the output signal is the
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* baseband BPSK signal and the imaginary part is the error
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* signal. When order=4, it can be used for quadrature modulations
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* where both I and Q (real and imaginary) are outputted.
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*
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* More details can be found online:
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*
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* J. Feigin, "Practical Costas loop design: Designing a simple and inexpensive
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* BPSK Costas loop carrier recovery circuit," RF signal processing, pp. 20-36,
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* 2002.
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*
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* http://rfdesign.com/images/archive/0102Feigin20.pdf
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*
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* \param alpha the loop gain used for phase adjustment
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* \param beta the loop gain for frequency adjustments
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* \param max_freq the maximum frequency deviation (radians/sample) the loop can handle
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* \param min_freq the minimum frequency deviation (radians/sample) the loop can handle
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* \param order the loop order, either 2 or 4 (enable PI/4 hack if order < 0)
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*/
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class repeater_costas_loop_cc;
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typedef boost::shared_ptr<repeater_costas_loop_cc> repeater_costas_loop_cc_sptr;
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repeater_costas_loop_cc_sptr
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repeater_make_costas_loop_cc (float alpha, float beta,
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float max_freq, float min_freq,
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int order
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) throw (std::invalid_argument);
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/*!
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* \brief Carrier tracking PLL for QPSK
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* \ingroup sync_blk
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* input: complex; output: complex
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* <br>The Costas loop can have two output streams:
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* stream 1 is the baseband I and Q;
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* stream 2 is the normalized frequency of the loop
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*
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* \p order must be 2 or 4.
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*/
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class repeater_costas_loop_cc : public gr_sync_block
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{
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friend repeater_costas_loop_cc_sptr repeater_make_costas_loop_cc (float alpha, float beta,
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float max_freq, float min_freq,
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int order
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) throw (std::invalid_argument);
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float d_alpha, d_beta, d_max_freq, d_min_freq, d_phase, d_freq;
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int d_order;
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repeater_costas_loop_cc (float alpha, float beta,
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float max_freq, float min_freq,
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int order
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) throw (std::invalid_argument);
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/*! \brief the phase detector circuit for fourth-order loops
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* \param sample complex sample
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* \return the phase error
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*/
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float phase_detector_4(gr_complex sample) const; // for QPSK
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/*! \brief the phase detector circuit for second-order loops
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* \param sample a complex sample
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* \return the phase error
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*/
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float phase_detector_2(gr_complex sample) const; // for BPSK
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float (repeater_costas_loop_cc::*d_phase_detector)(gr_complex sample) const;
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unsigned int d_interp_counter;
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bool d_rot45;
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public:
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/*! \brief set the first order gain
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* \param alpha
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*/
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void set_alpha(float alpha);
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/*! \brief get the first order gain
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*
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*/
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float alpha() const { return d_alpha; }
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/*! \brief set the second order gain
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* \param beta
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*/
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void set_beta(float beta);
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/*! \brief get the second order gain
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*
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*/
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float beta() const { return d_beta; }
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int work (int noutput_items,
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gr_vector_const_void_star &input_items,
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gr_vector_void_star &output_items);
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/*! \brief returns the current NCO frequency in radians/sample
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*
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*/
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float freq() const { return d_freq; }
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};
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#endif
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