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/* -*- c++ -*- */
/*
* Copyright 2008,2010,2012 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 INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H
#define INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H
#include <digital/api.h>
#include <gr_sync_block.h>
namespace gr {
namespace digital {
/*!
* \ingroup coding_blk
*
* Scramble an input stream using an LFSR. This block works on the
* LSB only of the input data stream, i.e., on an "unpacked
* binary" stream, and produces the same format on its output.
*/
class DIGITAL_API additive_scrambler_bb : virtual public gr_sync_block
{
public:
// gr::digital::additive_scrambler_bb::sptr
typedef boost::shared_ptr<additive_scrambler_bb> sptr;
/*!
* \brief Create additive scrambler.
*
* Scramble an input stream using an LFSR. This block works on
* the LSB only of the input data stream, i.e., on an "unpacked
* binary" stream, and produces the same format on its output.
*
* \param mask Polynomial mask for LFSR
* \param seed Initial shift register contents
* \param len Shift register length
* \param count Number of bits after which shift register is reset, 0=never
*
* The scrambler works by XORing the incoming bit stream by the
* output of the LFSR. Optionally, after 'count' bits have been
* processed, the shift register is reset to the seed value.
* This allows processing fixed length vectors of samples.
*/
static sptr make(int mask, int seed, int len, int count=0);
virtual int mask() const = 0;
virtual int seed() const = 0;
virtual int len() const = 0;
virtual int count() const = 0;
};
} /* namespace digital */
} /* namespace gr */
#endif /* INCLUDED_DIGITAL_ADDITIVE_SCRAMBLER_BB_H */
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