3 * Copyright 2002 Free Software Foundation, Inc.
5 * This file is part of GNU Radio
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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)
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14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
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19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
23 #ifndef _ATSC_FS_CHECKER_NAIVE_H_
24 #define _ATSC_FS_CHECKER_NAIVE_H_
26 #include <atsci_fs_checker.h>
29 * \brief Naive concrete implementation of field sync checker
31 class atsci_fs_checker_naive : public atsci_fs_checker {
34 static const int SRSIZE = 1024; // must be power of two
35 int d_index; // points at oldest sample
36 float d_sample_sr[SRSIZE]; // sample shift register
37 atsc::syminfo d_tag_sr[SRSIZE]; // tag shift register
38 unsigned char d_bit_sr[SRSIZE]; // binary decision shift register
42 static const int OFFSET_511 = 0; // offset to PN 511 pattern
43 static const int LENGTH_511 = 511 + 4; // length of PN 511 pattern (+ 4 seg sync)
44 static const int OFFSET_2ND_63 = 578; // offset to second PN 63 pattern
45 static const int LENGTH_2ND_63 = 63; // length of PN 63 pattern
47 static unsigned char s_511[LENGTH_511]; // PN 511 pattern
48 static unsigned char s_63[LENGTH_2ND_63]; // PN 63 pattern
50 inline static int wrap (int index){ return index & (SRSIZE - 1); }
51 inline static int incr (int index){ return wrap (index + 1); }
52 inline static int decr (int index){ return wrap (index - 1); }
57 atsci_fs_checker_naive ();
58 ~atsci_fs_checker_naive ();
61 virtual void reset ();
62 void filter (float input_sample, atsc::syminfo input_tag,
63 float *output_sample, atsc::syminfo *output_tag);
67 //! return delay in samples from input to output
73 #endif /* _ATSC_FS_CHECKER_NAIVE_H_ */