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/* -*- c++ -*- */
/*
* Copyright 2015 Free Software Foundation, Inc.
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#include "atsc_basic_trellis_encoder.h"
#include <cassert>
namespace gr {
namespace dtv {
const unsigned char atsc_basic_trellis_encoder::next_state[32] = {
0, 1, 4, 5, 2, 3, 6, 7, 1, 0, 5, 4, 3, 2, 7, 6,
4, 5, 0, 1, 6, 7, 2, 3, 5, 4, 1, 0, 7, 6, 3, 2
};
const unsigned char atsc_basic_trellis_encoder::out_symbol[32] = {
0, 2, 4, 6, 1, 3, 5, 7, 0, 2, 4, 6, 1, 3, 5, 7,
4, 6, 0, 2, 5, 7, 1, 3, 4, 6, 0, 2, 5, 7, 1, 3
};
/*!
* 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 atsc_basic_trellis_encoder::encode(unsigned int input)
{
assert(input < 4);
int index = (state << 2) + input;
state = next_state[index];
return out_symbol[index];
}
} /* namespace dtv */
} /* namespace gr */
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