GNU Radio Manual and C++ API Reference 3.8.5.0
The Free & Open Software Radio Ecosystem
 
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depuncture_bb.h
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1/* -*- c++ -*- */
2/*
3 * Copyright 2013-2014 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_FEC_DEPUNCTURE_BB_H
24#define INCLUDED_FEC_DEPUNCTURE_BB_H
25
26#include <gnuradio/block.h>
27#include <gnuradio/fec/api.h>
28
29namespace gr {
30namespace fec {
31
32/*!
33 * \brief Depuncture a stream of samples.
34 * \ingroup error_coding_blk
35 *
36 * \details
37
38 * Depuncture a given block of input samples of \p puncsize. The
39 * items produced is based on the pattern \p puncpat. Basically,
40 * if:
41 *
42 * \code
43 * k = 0
44 * if _puncpat[i] == 1:
45 * out[i] = input[k++]
46 * else:
47 * out[i] = symbol # default sym=127
48 * \endcode
49 *
50 * This block is designed for unpacked bits - that is, every
51 * input sample is a bit, either a 1 or 0. It's possible to use
52 * packed bits as symbols, but the depuncturing will be done on
53 * the symbol level, not the bit level.
54 *
55 * \p puncpat is specified as a 32-bit integer that we can
56 * convert into the vector _puncpat used in the algorithm above:
57 *
58 * \code
59 * _puncpat = [0,...]
60 * for i in puncsize:
61 * _puncpat[i] = puncpat >> (puncsize-1-i)
62 * \endcode
63 *
64 * Example:
65 * \code
66 * puncsize = 8
67 * puncpat = 0xEF --> [1,1,1,0,1,1,1,1]
68 * input = [a, b, c, d, e, f, g, h]
69 * output = [a, b, c, 127, e, f, g, h]
70 * \endcode
71 *
72 * The gr.fec Python module provides a read_bitlist function
73 * that can turn a string of a puncture pattern into the correct
74 * integer form. The pattern of 0xEF could be specified as
75 * fec.readbitlist("11101111"). Also, this allows us to use
76 * puncsize=len("11101111") to make sure that our sizes are set
77 * up correctly for the pattern we want.
78 *
79 * The fec.extended_decoder takes in the puncture pattern
80 * directly as a string and uses the readbitlist inside to do
81 * the conversion.
82 *
83 * The \p delay parameter delays the application of the puncture
84 * pattern. This is equivalent to circularly rotating the \p
85 * puncpat by \p delay. Note that because of the circular shift,
86 * the delay should be between 0 and \p puncsize, but this is
87 * not enforced; the effective delay will simply be \p delay mod
88 * \p puncsize. A negative value here is ignored.
89 */
90class FEC_API depuncture_bb : virtual public block
91{
92public:
93 // gr::fec::depuncture_bb::sptr
94 typedef boost::shared_ptr<depuncture_bb> sptr;
95
96 /*!
97 * \brief Constructs a depuncture block.
98 *
99 * \param puncsize Size of block of bits to puncture
100 * \param puncpat The puncturing pattern
101 * \param delay Delayed the puncturing pattern by shifting it
102 * \param symbol The symbol to reinsert into the stream (def=127)
103 */
104 static sptr make(int puncsize, int puncpat, int delay = 0, char symbol = 127);
105};
106
107} /* namespace fec */
108} /* namespace gr */
109
110#endif /* INCLUDED_FEC_DEPUNCTURE_BB_H */
The abstract base class for all 'terminal' processing blocks.
Definition block.h:72
Depuncture a stream of samples.
Definition depuncture_bb.h:91
boost::shared_ptr< depuncture_bb > sptr
Definition depuncture_bb.h:94
static sptr make(int puncsize, int puncpat, int delay=0, char symbol=127)
Constructs a depuncture block.
#define FEC_API
Definition gr-fec/include/gnuradio/fec/api.h:30
GNU Radio logging wrapper for log4cpp library (C++ port of log4j)
Definition basic_block.h:46