GNU Radio 3.6.2 C++ API
digital_correlate_access_code_tag_bb.h
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1 /* -*- c++ -*- */
2 /*
3  * Copyright 2005,2006,2011,2012 Free Software Foundation, Inc.
4  *
5  * This file is part of GNU Radio
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7  * GNU Radio is free software; you can redistribute it and/or modify
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22 
23 #ifndef INCLUDED_digital_correlate_access_code_tag_bb_H
24 #define INCLUDED_digital_correlate_access_code_tag_bb_H
25 
26 #include <digital_api.h>
27 #include <gr_sync_block.h>
28 #include <string>
29 
32 
33 /*!
34  * \param access_code is represented with 1 byte per bit, e.g., "010101010111000100"
35  * \param threshold maximum number of bits that may be wrong
36  * \param tag_name key of the tag inserted into the tag stream
37  */
39 digital_make_correlate_access_code_tag_bb(const std::string &access_code,
40  int threshold,
41  const std::string &tag_name);
42 
43 /*!
44  * \brief Examine input for specified access code, one bit at a time.
45  * \ingroup sync_blk
46  *
47  * input: stream of bits, 1 bit per input byte (data in LSB)
48  * output: unaltered stream of bits (plus tags)
49  *
50  * This block annotates the input stream with tags. The tags have key
51  * name [tag_name], specified in the constructor. Used for searching
52  * an input data stream for preambles, etc.
53  */
55 {
57  digital_make_correlate_access_code_tag_bb(const std::string &access_code,
58  int threshold,
59  const std::string &tag_name);
60  private:
61  unsigned long long d_access_code; // access code to locate start of packet
62  // access code is left justified in the word
63  unsigned long long d_data_reg; // used to look for access_code
64  unsigned long long d_mask; // masks access_code bits (top N bits are set where
65  // N is the number of bits in the access code)
66  unsigned int d_threshold; // how many bits may be wrong in sync vector
67  unsigned int d_len; // the length of the access code
68 
69  pmt::pmt_t d_key, d_me; //d_key is the tag name, d_me is the block name + unique ID
70 
71  protected:
72  digital_correlate_access_code_tag_bb(const std::string &access_code,
73  int threshold,
74  const std::string &tag_name);
75 
76  public:
78 
79  int work(int noutput_items,
80  gr_vector_const_void_star &input_items,
81  gr_vector_void_star &output_items);
82 
83  /*!
84  * \param access_code is represented with 1 byte per bit, e.g., "010101010111000100"
85  */
86  bool set_access_code(const std::string &access_code);
87 };
88 
89 #endif /* INCLUDED_digital_correlate_access_code_tag_bb_H */