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   1 /*
   2  * Copyright 2009 Free Software Foundation, Inc.
   3  *
   4  * This file is part of GNU Radio
   5  *
   6  * GNU Radio is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 3, or (at your option)
   9  * any later version.
  10  *
  11  * GNU Radio is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with GNU Radio; see the file COPYING.  If not, write to
  18  * the Free Software Foundation, Inc., 51 Franklin Street,
  19  * Boston, MA 02110-1301, USA.
  20  */
  21
  22 #include <gr_channel_model.h>
  23 #include <gr_io_signature.h>
  24 #include <gr_sig_source_f.h>
  25 #include <iostream>
  26
  27 // Shared pointer constructor
  28 gr_channel_model_sptr
  29 gr_make_channel_model(double noise_voltage,
  30                       double frequency_offset,
  31                       double epsilon,
  32                       const std::vector<gr_complex> &taps,
  33                       double noise_seed)
  34 {
  35   return gnuradio::get_initial_sptr(new gr_channel_model(noise_voltage,
  36                                                          frequency_offset,
  37                                                          epsilon,
  38                                                          taps,
  39                                                          noise_seed));
  40 }
  41
  42 // Hierarchical block constructor
  43 gr_channel_model::gr_channel_model(double noise_voltage,
  44                                    double frequency_offset,
  45                                    double epsilon,
  46                                    const std::vector<gr_complex> &taps,
  47                                    double noise_seed)
  48   : gr_hier_block2("gr_channel_model",
  49                    gr_make_io_signature(1, 1, sizeof(gr_complex)),
  50                    gr_make_io_signature(1, 1, sizeof(gr_complex)))
  51 {
  52   d_taps = taps;
  53   while(d_taps.size() < 2) {
  54     d_taps.push_back(0);
  55   }
  56
  57   d_timing_offset = gr_make_fractional_interpolator_cc(0, epsilon);
  58
  59   d_multipath = gr_make_fir_filter_ccc(1, d_taps);
  60
  61   d_noise_adder = gr_make_add_cc();
  62   d_noise = gr_make_noise_source_c(GR_GAUSSIAN, noise_voltage, noise_seed);
  63   d_freq_offset = gr_make_sig_source_c(1, GR_SIN_WAVE, frequency_offset, 1.0, 0.0);
  64   d_mixer_offset = gr_make_multiply_cc();
  65
  66   connect(self(), 0, d_timing_offset, 0);
  67   connect(d_timing_offset, 0, d_multipath, 0);
  68   connect(d_multipath, 0, d_mixer_offset, 0);
  69   connect(d_freq_offset, 0, d_mixer_offset, 1);
  70   connect(d_mixer_offset, 0, d_noise_adder, 1);
  71   connect(d_noise, 0, d_noise_adder, 0);
  72   connect(d_noise_adder, 0, self(), 0);
  73 }
  74
  75 void
  76 gr_channel_model::set_noise_voltage(double noise_voltage)
  77 {
  78   d_noise->set_amplitude(noise_voltage);
  79 }
  80
  81 void
  82 gr_channel_model::set_frequency_offset(double frequency_offset)
  83 {
  84   d_freq_offset->set_frequency(frequency_offset);
  85 }
  86
  87 void
  88 gr_channel_model::set_taps(const std::vector<gr_complex> &taps)
  89 {
  90   d_taps = taps;
  91   while(d_taps.size() < 2) {
  92     d_taps.push_back(0);
  93   }
  94   d_multipath->set_taps(d_taps);
  95 }
  96
  97 void
  98 gr_channel_model::set_timing_offset(double epsilon)
  99 {
 100   d_timing_offset->set_interp_ratio(epsilon);
 101 }