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/* -*- c++ -*- */
/*
* Copyright 2002 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
*
* GNU Radio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef _ATSC_FS_CHECKER_NAIVE_H_
#define _ATSC_FS_CHECKER_NAIVE_H_
#include <atsci_fs_checker.h>
/*!
* \brief Naive concrete implementation of field sync checker
*/
class atsci_fs_checker_naive : public atsci_fs_checker {
private:
static const int SRSIZE = 1024; // must be power of two
int d_index; // points at oldest sample
float d_sample_sr[SRSIZE]; // sample shift register
atsc::syminfo d_tag_sr[SRSIZE]; // tag shift register
unsigned char d_bit_sr[SRSIZE]; // binary decision shift register
int d_field_num;
int d_segment_num;
static const int OFFSET_511 = 0; // offset to PN 511 pattern
static const int LENGTH_511 = 511 + 4; // length of PN 511 pattern (+ 4 seg sync)
static const int OFFSET_2ND_63 = 578; // offset to second PN 63 pattern
static const int LENGTH_2ND_63 = 63; // length of PN 63 pattern
static unsigned char s_511[LENGTH_511]; // PN 511 pattern
static unsigned char s_63[LENGTH_2ND_63]; // PN 63 pattern
inline static int wrap (int index){ return index & (SRSIZE - 1); }
inline static int incr (int index){ return wrap (index + 1); }
inline static int decr (int index){ return wrap (index - 1); }
public:
// CREATORS
atsci_fs_checker_naive ();
~atsci_fs_checker_naive ();
// MANIPULATORS
virtual void reset ();
void filter (float input_sample, atsc::syminfo input_tag,
float *output_sample, atsc::syminfo *output_tag);
// ACCESSORS
//! return delay in samples from input to output
int delay () const;
};
#endif /* _ATSC_FS_CHECKER_NAIVE_H_ */
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