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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 2, 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_BASIC_TRELLIS_ENCODER_H_
#define _ATSC_BASIC_TRELLIS_ENCODER_H_
#include <assert.h>
/*!
* \brief ATSC trellis encoder building block.
*
* Note this is NOT the 12x interleaved interface.
*
* This implements a single instance of the ATSC trellis encoder.
* This is a rate 2/3 encoder (really a constraint length 3, rate 1/2
* encoder with the top bit passed through unencoded. This does not
* implement the "precoding" of the top bit, because the NTSC rejection
* filter is not supported.
*/
class atsci_basic_trellis_encoder {
private:
int state; // two bit state;
public:
atsci_basic_trellis_encoder () : state (0) {}
/*!
* Encode two bit INPUT into 3 bit return value. Domain is [0,3],
* Range is [0,7]. The mapping to bipolar levels is not done.
*/
int encode (unsigned int input);
//! reset encoder state
void reset () { state = 0; }
static const unsigned char next_state[32];
static const unsigned char out_symbol[32];
};
#endif /* _ATSC_BASIC_TRELLIS_ENCODER_H_ */
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