GNU Radio Manual and C++ API Reference  3.7.13.4
The Free & Open Software Radio Ecosystem
lfsr_32k.h
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1 /* -*- c++ -*- */
2 /*
3  * Copyright 2004,2013 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_32k_H
24 #define INCLUDED_GRI_LFSR_32k_H
25 
26 #include <gnuradio/blocks/api.h>
28 
29 namespace gr {
30  namespace blocks {
31 
32  /*!
33  * \brief generate pseudo-random sequence of length 32768 bits.
34  * \ingroup misc
35  *
36  * \details
37  * This is based on gri_lfsr_15_1_0 with an extra 0 added at the
38  * end of the sequence.
39  */
41  {
42  private:
43  lfsr_15_1_0 d_lfsr;
44  unsigned int d_count;
45 
46  public:
47  lfsr_32k() { reset (); }
48 
49  void reset()
50  {
51  d_lfsr.reset();
52  d_count = 0;
53  }
54 
55  int next_bit()
56  {
57  if(d_count == 32767) {
58  d_count = 0;
59  return 0;
60  }
61  d_count++;
62  return d_lfsr.next_bit();
63  }
64 
65  int next_byte()
66  {
67  int v = 0;
68  for(int i = 0; i < 8; i++) {
69  v >>= 1;
70  if(next_bit ())
71  v |= 0x80;
72  }
73  return v;
74  }
75 
76  int next_short()
77  {
78  int v = 0;
79  for(int i = 0; i < 16; i++) {
80  v >>= 1;
81  if(next_bit ())
82  v |= 0x8000;
83  }
84  return v;
85  }
86  };
87 
88  } /* namespace blocks */
89 } /* namespace gr */
90 
91 #endif /* INCLUDED_GRI_LFSR_32k_H */
void reset()
Definition: lfsr_15_1_0.h:47
generate pseudo-random sequence of length 32768 bits.
Definition: lfsr_32k.h:40
void reset()
Definition: lfsr_32k.h:49
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:695
lfsr_32k()
Definition: lfsr_32k.h:47
int next_bit()
Definition: lfsr_32k.h:55
#define BLOCKS_API
Definition: gr-blocks/include/gnuradio/blocks/api.h:30
int next_bit()
Definition: lfsr_15_1_0.h:49
int next_byte()
Definition: lfsr_32k.h:65
int next_short()
Definition: lfsr_32k.h:76