3 * Copyright 2008,2010 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
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13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
22 #ifndef INCLUDED_GR_ADDITIVE_SCRAMBLER_BB_H
23 #define INCLUDED_GR_ADDITIVE_SCRAMBLER_BB_H
25 #include <gr_sync_block.h>
28 class gr_additive_scrambler_bb;
29 typedef boost::shared_ptr<gr_additive_scrambler_bb> gr_additive_scrambler_bb_sptr;
31 gr_additive_scrambler_bb_sptr gr_make_additive_scrambler_bb(int mask, int seed, int len, int count=0);
34 * Scramble an input stream using an LFSR. This block works on the LSB only
35 * of the input data stream, i.e., on an "unpacked binary" stream, and
36 * produces the same format on its output.
38 * \param mask Polynomial mask for LFSR
39 * \param seed Initial shift register contents
40 * \param len Shift register length
41 * \param count Number of bits after which shift register is reset, 0=never
43 * The scrambler works by XORing the incoming bit stream by the output of
44 * the LFSR. Optionally, after 'count' bits have been processed, the shift
45 * register is reset to the seed value. This allows processing fixed length
51 class gr_additive_scrambler_bb : public gr_sync_block
53 friend gr_additive_scrambler_bb_sptr gr_make_additive_scrambler_bb(int mask, int seed, int len, int count);
59 gr_additive_scrambler_bb(int mask, int seed, int len, int count);
62 int work(int noutput_items,
63 gr_vector_const_void_star &input_items,
64 gr_vector_void_star &output_items);
67 #endif /* INCLUDED_GR_ADDITIVE_SCRAMBLER_BB_H */