GNU Radio 3.7.2git-47-g5cfb1151 C++ API
additive_scrambler_bb.h
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1 /* -*- c++ -*- */
2 /*
3  * Copyright 2008,2010,2012 Free Software Foundation, Inc.
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5  * This file is part of GNU Radio
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22 
23 #ifndef INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H
24 #define INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H
25 
26 #include <gnuradio/digital/api.h>
27 #include <gnuradio/sync_block.h>
28 
29 namespace gr {
30  namespace digital {
31 
32  /*!
33  * \ingroup coding_blk
34  *
35  * \brief
36  * Scramble an input stream using an LFSR.
37  *
38  * \details
39  * This block works on the LSB only of the input data stream,
40  * i.e., on an "unpacked binary" stream, and produces the same
41  * format on its output.
42  *
43  * The scrambler works by XORing the incoming bit stream by the
44  * output of the LFSR. Optionally, after 'count' bits have been
45  * processed, the shift register is reset to the seed value.
46  * This allows processing fixed length vectors of samples.
47  */
49  {
50  public:
51  // gr::digital::additive_scrambler_bb::sptr
53 
54  /*!
55  * \brief Create additive scrambler.
56  *
57  * \param mask Polynomial mask for LFSR
58  * \param seed Initial shift register contents
59  * \param len Shift register length
60  * \param count Number of bytes after which shift register is reset, 0=never
61  * \param bits_per_byte Number of bits per byte
62  * \param reset_tag When a tag with this key is detected, the shift register is reset (when this is set, count is ignored!)
63  */
64  static sptr make(int mask, int seed, int len, int count=0, int bits_per_byte=1, const std::string &reset_tag_key="");
65 
66  virtual int mask() const = 0;
67  virtual int seed() const = 0;
68  virtual int len() const = 0;
69  virtual int count() const = 0;
70  virtual int bits_per_byte() = 0;
71  };
72 
73  } /* namespace digital */
74 } /* namespace gr */
75 
76 #endif /* INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H */