GNU Radio 3.6.5 C++ API

lfsr_32k.h

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00001 /* -*- c++ -*- */
00002 /*
00003  * Copyright 2004,2013 Free Software Foundation, Inc.
00004  *
00005  * This file is part of GNU Radio
00006  *
00007  * GNU Radio is free software; you can redistribute it and/or modify
00008  * it under the terms of the GNU General Public License as published by
00009  * the Free Software Foundation; either version 3, or (at your option)
00010  * any later version.
00011  *
00012  * GNU Radio is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015  * GNU General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU General Public License
00018  * along with GNU Radio; see the file COPYING.  If not, write to
00019  * the Free Software Foundation, Inc., 51 Franklin Street,
00020  * Boston, MA 02110-1301, USA.
00021  */
00022 
00023 #ifndef INCLUDED_GRI_LFSR_32k_H
00024 #define INCLUDED_GRI_LFSR_32k_H
00025 
00026 #include <blocks/api.h>
00027 #include <blocks/lfsr_15_1_0.h>
00028 
00029 namespace gr {
00030   namespace blocks {
00031 
00032     /*!
00033      * \brief generate pseudo-random sequence of length 32768 bits.
00034      * \ingroup misc
00035      *
00036      * \details
00037      * This is based on gri_lfsr_15_1_0 with an extra 0 added at the
00038      * end of the sequence.
00039      */
00040     class BLOCKS_API lfsr_32k
00041     {
00042     private:
00043       lfsr_15_1_0 d_lfsr;
00044       unsigned int d_count;
00045 
00046     public:
00047       lfsr_32k() { reset (); }
00048 
00049       void reset()
00050       {
00051         d_lfsr.reset();
00052         d_count = 0;
00053       }
00054 
00055       int next_bit()
00056       {
00057         if(d_count == 32767) {
00058           d_count = 0;
00059           return 0;
00060         }
00061         d_count++;
00062         return d_lfsr.next_bit();
00063       }
00064 
00065       int next_byte()
00066       {
00067         int     v = 0;
00068         for(int i = 0; i < 8; i++) {
00069           v >>= 1;
00070           if(next_bit ())
00071             v |= 0x80;
00072         }
00073         return v;
00074       }
00075 
00076       int next_short()
00077       {
00078         int v = 0;
00079         for(int i = 0; i < 16; i++) {
00080           v >>= 1;
00081           if(next_bit ())
00082             v |= 0x8000;
00083         }
00084         return v;
00085       }
00086     };
00087 
00088   } /* namespace blocks */
00089 } /* namespace gr */
00090 
00091 #endif /* INCLUDED_GRI_LFSR_32k_H */