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+/* -*- c++ -*- */
+/*
+ * Copyright 2011,2012 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio 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.
+ *
+ * GNU Radio 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 GNU Radio; 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 "constellation_receiver_cb_impl.h"
+#include <gr_io_signature.h>
+#include <gr_prefs.h>
+#include <gr_math.h>
+#include <gr_expj.h>
+#include <stdexcept>
+
+namespace gr {
+ namespace digital {
+
+#define M_TWOPI (2*M_PI)
+#define VERBOSE_MM 0 // Used for debugging symbol timing loop
+#define VERBOSE_COSTAS 0 // Used for debugging phase and frequency tracking
+
+ constellation_receiver_cb::sptr
+ constellation_receiver_cb::make(constellation_sptr constell,
+ float loop_bw, float fmin, float fmax)
+ {
+ return gnuradio::get_initial_sptr
+ (new constellation_receiver_cb_impl(constell, loop_bw,
+ fmin, fmax));
+ }
+
+ static int ios[] = {sizeof(char), sizeof(float), sizeof(float), sizeof(float)};
+ static std::vector<int> iosig(ios, ios+sizeof(ios)/sizeof(int));
+ constellation_receiver_cb_impl::constellation_receiver_cb_impl(constellation_sptr constellation,
+ float loop_bw, float fmin, float fmax)
+ : gr_block("constellation_receiver_cb",
+ gr_make_io_signature(1, 1, sizeof(gr_complex)),
+ gr_make_io_signaturev(1, 4, iosig)),
+ gri_control_loop(loop_bw, fmax, fmin),
+ d_constellation(constellation),
+ d_current_const_point(0)
+ {
+ if(d_constellation->dimensionality() != 1)
+ throw std::runtime_error("This receiver only works with constellations of dimension 1.");
+ }
+
+ constellation_receiver_cb_impl::~constellation_receiver_cb_impl()
+ {
+ }
+
+ void
+ constellation_receiver_cb_impl::phase_error_tracking(float phase_error)
+ {
+ advance_loop(phase_error);
+ phase_wrap();
+ frequency_limit();
+
+#if VERBOSE_COSTAS
+ printf("cl: phase_error: %f phase: %f freq: %f sample: %f+j%f constellation: %f+j%f\n",
+ phase_error, d_phase, d_freq, sample.real(), sample.imag(),
+ d_constellation->points()[d_current_const_point].real(),
+ d_constellation->points()[d_current_const_point].imag());
+#endif
+ }
+
+ int
+ constellation_receiver_cb_impl::general_work(int noutput_items,
+ gr_vector_int &ninput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items)
+ {
+ const gr_complex *in = (const gr_complex *)input_items[0];
+ unsigned char *out = (unsigned char *)output_items[0];
+
+ int i=0;
+
+ float phase_error;
+ unsigned int sym_value;
+ gr_complex sample, nco;
+
+ float *out_err = 0, *out_phase = 0, *out_freq = 0;
+ if(output_items.size() == 4) {
+ out_err = (float*)output_items[1];
+ out_phase = (float*)output_items[2];
+ out_freq = (float*)output_items[3];
+ }
+
+ while((i < noutput_items) && (i < ninput_items[0])) {
+ sample = in[i];
+ nco = gr_expj(d_phase); // get the NCO value for derotating the current sample
+ sample = nco*sample; // get the downconverted symbol
+
+ sym_value = d_constellation->decision_maker_pe(&sample, &phase_error);
+ phase_error_tracking(phase_error); // corrects phase and frequency offsets
+
+ out[i] = sym_value;
+
+ if(output_items.size() == 4) {
+ out_err[i] = phase_error;
+ out_phase[i] = d_phase;
+ out_freq[i] = d_freq;
+ }
+ i++;
+ }
+
+ consume_each(i);
+ return i;
+ }
+
+ } /* namespace digital */
+} /* namespace gr */
+