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gr_check_lfsr_32k_s.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 #ifndef INCLUDED_GR_CHECK_LFSR_32K_S_H
23 #define INCLUDED_GR_CHECK_LFSR_32K_S_H
24 
25 #include <gr_core_api.h>
26 #include <gr_sync_block.h>
27 #include <gri_lfsr_32k.h>
28 
29 
32 
34 
35 /*!
36  * \brief sink that checks if its input stream consists of a lfsr_32k sequence.
37  * \ingroup sink_blk
38  *
39  * This sink is typically used along with gr_lfsr_32k_source_s to test
40  * the USRP using its digital loopback mode.
41  */
43 {
45 
46  enum state {
47  SEARCHING, // searching for synchronization
48  MATCH0,
49  MATCH1,
50  MATCH2,
51  LOCKED // is locked
52  };
53 
54  state d_state;
55  unsigned int d_history; // bitmask of decisions
56 
57  long d_ntotal; // total number of shorts
58  long d_nright; // # of correct shorts
59  long d_runlength; // # of correct shorts in a row
60 
61  static const int BUFSIZE = 2048 - 1; // ensure pattern isn't packet aligned
62  int d_index;
63  unsigned short d_buffer[BUFSIZE];
64 
65 
67 
68  void enter_SEARCHING ();
69  void enter_MATCH0 ();
70  void enter_MATCH1 ();
71  void enter_MATCH2 ();
72  void enter_LOCKED ();
73 
74  void right (){
75  d_history = (d_history << 1) | 0x1;
76  d_nright++;
77  d_runlength++;
78  }
79 
80  void wrong (){
81  d_history = (d_history << 1) | 0x0;
82  d_runlength = 0;
83  }
84 
85  bool right_three_times () { return (d_history & 0x7) == 0x7; }
86  bool wrong_three_times () { return (d_history & 0x7) == 0x0; }
87 
88  void log_error (unsigned short expected, unsigned short actual);
89 
90  public:
91 
92  int work (int noutput_items,
93  gr_vector_const_void_star &input_items,
94  gr_vector_void_star &output_items);
95 
96  long ntotal () const { return d_ntotal; }
97  long nright () const { return d_nright; }
98  long runlength () const { return d_runlength; }
99 
100 };
101 
102 
103 #endif /* INCLUDED_GR_CHECK_LFSR_32K_S_H */