GNU Radio Manual and C++ API Reference  3.7.9.2
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lfsr_15_1_0.h
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1 /* -*- c++ -*- */
2 /*
3  * Copyright 2004 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_GRI_LFSR_15_1_0_H
24 #define INCLUDED_GRI_LFSR_15_1_0_H
25 
26 #include <gnuradio/blocks/api.h>
27 
28 namespace gr {
29  namespace blocks {
30 
31  /*!
32  * \brief Linear Feedback Shift Register using primitive polynomial x^15 + x + 1
33  * \ingroup misc
34  *
35  * \details
36  * Generates a maximal length pseudo-random sequence of length
37  * 2^15 - 1 bits.
38  */
40  {
41  private:
42  unsigned long d_sr; // shift register
43 
44  public:
45  lfsr_15_1_0() { reset(); }
46 
47  void reset() { d_sr = 0x7fff; }
48 
49  int next_bit()
50  {
51  d_sr = ((((d_sr >> 1) ^ d_sr) & 0x1) << 14) | (d_sr >> 1);
52  return d_sr & 0x1;
53  }
54 
55  int next_byte ()
56  {
57  int v = 0;
58  for(int i = 0; i < 8; i++) {
59  v >>= 1;
60  if(next_bit ())
61  v |= 0x80;
62  }
63  return v;
64  }
65  };
66 
67  } /* namespace blocks */
68 } /* namespace gr */
69 
70 #endif /* INCLUDED_GRI_LFSR_15_1_0_H */
lfsr_15_1_0()
Definition: lfsr_15_1_0.h:45
void reset()
Definition: lfsr_15_1_0.h:47
int next_byte()
Definition: lfsr_15_1_0.h:55
Linear Feedback Shift Register using primitive polynomial x^15 + x + 1.
Definition: lfsr_15_1_0.h:39
Definition: cc_common.h:45
Include this header to use the message passing features.
Definition: logger.h:131
#define BLOCKS_API
Definition: gr-blocks/include/gnuradio/blocks/api.h:30
int next_bit()
Definition: lfsr_15_1_0.h:49