GNU Radio Manual and C++ API Reference  3.7.9.2
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fs_checker_impl.h
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1 /* -*- c++ -*- */
2 /*
3  * Copyright 2002 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 _ATSC_FS_CHECKER_H_
23 #define _ATSC_FS_CHECKER_H_
24 
25 #include <gnuradio/atsc/api.h>
27 
28 /*!
29  * \brief abstract base class for ATSC field sync checker
30  *
31  * Processes input samples one at a time looking for
32  * an occurence of either the field sync 1 or field sync 2 pattern.
33  *
34  * Note that unlike atsci_fs_correlator, this class uses the symbol_num in
35  * input_tag to avoid having to test each symbol position.
36  *
37  * For each sample processed, an output sample and an output tag are produced.
38  * The output samples are identical to the input samples but are delayed by
39  * a number of samples given by \p delay(). The output tag associated with
40  * the the given output sample indicates whether this sample is the beginning
41  * of one of the field syncs or is an ordinary sample. The tags are defined in
42  * atsci_sync_tag.h.
43  *
44  * For ease of use, the field sync patterns are defined to begin with the
45  * first symbol of the 4 symbol data segment sync pattern that immediately
46  * proceeds the actual PN 511 code. This makes it easier for downstream code
47  * to determine the location of data segment syncs merely by counting. They'll
48  * occur every 832 samples assuming everything is working.
49  */
50 
52 
53 public:
54 
55  // CREATORS
57  virtual ~atsci_fs_checker () = 0;
58 
59  // MANIPULATORS
60  virtual void reset () = 0;
61  virtual void filter (float input_sample, atsc::syminfo input_tag,
62  float *output_sample, atsc::syminfo *output_tag) = 0;
63 
64  // ACCESSORS
65 
66  //! return delay in samples from input to output
67  virtual int delay () const = 0;
68 };
69 
70 #endif /* _ATSC_FS_CHECKER_H_ */
#define ATSC_API
Definition: gr-atsc/include/gnuradio/atsc/api.h:30
Definition: syminfo_impl.h:30
abstract base class for ATSC field sync checker
Definition: fs_checker_impl.h:51