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Diffstat (limited to 'gr-digital/lib/digital_constellation_receiver_cb.cc')
| -rw-r--r-- | gr-digital/lib/digital_constellation_receiver_cb.cc | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/gr-digital/lib/digital_constellation_receiver_cb.cc b/gr-digital/lib/digital_constellation_receiver_cb.cc new file mode 100644 index 000000000..b9239962a --- /dev/null +++ b/gr-digital/lib/digital_constellation_receiver_cb.cc @@ -0,0 +1,123 @@ +/* -*- c++ -*- */ +/* + * Copyright 2011 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 <gr_io_signature.h> +#include <gr_prefs.h> +#include <digital_constellation_receiver_cb.h> +#include <stdexcept> +#include <gr_math.h> +#include <gr_expj.h> + + +#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 + +// Public constructor + +digital_constellation_receiver_cb_sptr +digital_make_constellation_receiver_cb(digital_constellation_sptr constell, + float loop_bw, float fmin, float fmax) +{ + return gnuradio::get_initial_sptr(new digital_constellation_receiver_cb (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)); +digital_constellation_receiver_cb::digital_constellation_receiver_cb (digital_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."); +} + +void +digital_constellation_receiver_cb::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 +digital_constellation_receiver_cb::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; +} + |