GNU Radio Manual and C++ API Reference 3.8.5.0
The Free & Open Software Radio Ecosystem
 
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channel_model2.h
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1/* -*- c++ -*- */
2/*
3 * Copyright 2009,2012,2013 Free Software Foundation, Inc.
4 *
5 * This file is part of GNU Radio
6 *
7 * GNU Radio is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
10 * any later version.
11 *
12 * GNU Radio is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
21 */
22
23#ifndef INCLUDED_CHANNELS_CHANNEL_MODEL2_H
24#define INCLUDED_CHANNELS_CHANNEL_MODEL2_H
25
28#include <gnuradio/types.h>
29
30namespace gr {
31namespace channels {
32
33/*!
34 * \brief Basic channel simulator allowing time-varying frequency
35 * and timing inputs.
36 * \ingroup channel_models_blk
37 *
38 * \details
39 * This block implements a basic channel model simulator that can
40 * be used to help evaluate, design, and test various signals,
41 * waveforms, and algorithms.
42 *
43 * This model allows the user to set the voltage of an AWGN noise
44 * source (\p noise_voltage), an initial timing offset (\p
45 * epsilon), and a seed (\p noise_seed) to randomize the AWGN
46 * noise source.
47 *
48 * Multipath can be approximated in this model by using a FIR
49 * filter representation of a multipath delay profile with the
50 * parameter \p taps.
51 *
52 * Unlike gr::channels::channel_model, this block is designed to
53 * enable time-varying frequency and timing offsets.
54 * * Port 0: input signal to be run through the channel.
55 * * Port 1: frequency function. A constant value between -0.5 and
56 * 0.5 here will turn into a constant frequency offset
57 * from -fs/2 to fs/2 (where fs is the sample rate).
58 * * Port 2: timing offset function. Sets the resampling rate of
59 * the channel model. A constant value here produces
60 * that value as the timing offset, so a constant 1.0
61 * input stream is the same as not having a timing
62 * offset.
63 *
64 * Since the models for frequency and timing offset may vary and
65 * what we are trying to model may be different for different
66 * simulations, we provide the time-varying nature as an input
67 * function that is user-defined. If only constant frequency and
68 * timing offsets are required, it is easier and less expensive to
69 * use gr::channels::channel_model.
70 */
72{
73public:
74 // gr::channels::channel_model2::sptr
75 typedef boost::shared_ptr<channel_model2> sptr;
76
77 /*! \brief Build the channel simulator.
78 *
79 * \param noise_voltage The AWGN noise level as a voltage (to be
80 * calculated externally to meet, say, a
81 * desired SNR).
82 * \param epsilon The initial sample timing offset to emulate the
83 * different rates between the sample clocks of
84 * the transmitter and receiver. 1.0 is no difference.
85 * \param taps Taps of a FIR filter to emulate a multipath delay profile.
86 * \param noise_seed A random number generator seed for the noise source.
87 * \param block_tags If true, tags will not be able to propagate through this block.
88 */
89 static sptr make(double noise_voltage = 0.0,
90 double epsilon = 1.0,
91 const std::vector<gr_complex>& taps = std::vector<gr_complex>(1, 1),
92 double noise_seed = 0,
93 bool block_tags = false);
94
95 virtual void set_noise_voltage(double noise_voltage) = 0;
96 virtual void set_taps(const std::vector<gr_complex>& taps) = 0;
97 virtual void set_timing_offset(double epsilon) = 0;
98
99 virtual double noise_voltage() const = 0;
100 virtual std::vector<gr_complex> taps() const = 0;
101 virtual double timing_offset() const = 0;
102};
103
104} /* namespace channels */
105} /* namespace gr */
106
107#endif /* INCLUDED_CHANNELS_CHANNEL_MODEL2_H */
Basic channel simulator allowing time-varying frequency and timing inputs.
Definition channel_model2.h:72
boost::shared_ptr< channel_model2 > sptr
Definition channel_model2.h:75
virtual void set_noise_voltage(double noise_voltage)=0
virtual double timing_offset() const =0
virtual void set_timing_offset(double epsilon)=0
virtual double noise_voltage() const =0
virtual std::vector< gr_complex > taps() const =0
virtual void set_taps(const std::vector< gr_complex > &taps)=0
static sptr make(double noise_voltage=0.0, double epsilon=1.0, const std::vector< gr_complex > &taps=std::vector< gr_complex >(1, 1), double noise_seed=0, bool block_tags=false)
Build the channel simulator.
Hierarchical container class for gr::block's and gr::hier_block2's.
Definition hier_block2.h:46
#define CHANNELS_API
Definition gr-channels/include/gnuradio/channels/api.h:30
static const float taps[NSTEPS+1][NTAPS]
Definition interpolator_taps.h:9
GNU Radio logging wrapper for log4cpp library (C++ port of log4j)
Definition basic_block.h:46