GNU Radio Manual and C++ API Reference 3.7.14.0
The Free & Open Software Radio Ecosystem
additive_scrambler_bb.h
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1/* -*- c++ -*- */
2/*
3 * Copyright 2008,2010,2012 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
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21 */
22
23#ifndef INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H
24#define INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H
25
27#include <gnuradio/sync_block.h>
28
29namespace gr {
30namespace digital {
31
32/*!
33 * \ingroup coding_blk
34 *
35 * \brief
36 * Scramble an input stream using an LFSR.
37 *
38 * \details
39 * This block scrambles up to 8 bits per byte of the input
40 * data stream, starting at the LSB.
41 *
42 * The scrambler works by XORing the incoming bit stream by the
43 * output of the LFSR. Optionally, after \p count bits have been
44 * processed, the shift register is reset to the \p seed value.
45 * This allows processing fixed length vectors of samples.
46 *
47 * Alternatively, the LFSR can be reset using a reset tag to
48 * scramble variable length vectors. However, it cannot be reset
49 * between bytes.
50 *
51 * For details on configuring the LFSR, see gr::digital::lfsr.
52 */
54{
55public:
56 // gr::digital::additive_scrambler_bb::sptr
57 typedef boost::shared_ptr<additive_scrambler_bb> sptr;
58
59 /*!
60 * \brief Create additive scrambler.
61 *
62 * \param mask Polynomial mask for LFSR
63 * \param seed Initial shift register contents
64 * \param len Shift register length
65 * \param count Number of bytes after which shift register is reset, 0=never
66 * \param bits_per_byte Number of bits per byte
67 * \param reset_tag_key When a tag with this key is detected, the shift register is
68 * reset (when this is set, count is ignored!)
69 */
70 static sptr make(int mask,
71 int seed,
72 int len,
73 int count = 0,
74 int bits_per_byte = 1,
75 const std::string& reset_tag_key = "");
76
77 virtual int mask() const = 0;
78 virtual int seed() const = 0;
79 virtual int len() const = 0;
80 virtual int count() const = 0;
81 virtual int bits_per_byte() = 0;
82};
83
84} /* namespace digital */
85} /* namespace gr */
86
87#endif /* INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H */
Scramble an input stream using an LFSR.
Definition: additive_scrambler_bb.h:54
virtual int len() const =0
virtual int seed() const =0
virtual int count() const =0
boost::shared_ptr< additive_scrambler_bb > sptr
Definition: additive_scrambler_bb.h:57
static sptr make(int mask, int seed, int len, int count=0, int bits_per_byte=1, const std::string &reset_tag_key="")
Create additive scrambler.
virtual int mask() const =0
synchronous 1:1 input to output with history
Definition: sync_block.h:38
#define DIGITAL_API
Definition: gr-digital/include/gnuradio/digital/api.h:30
Include this header to use the message passing features.
Definition: basic_block.h:45