GNU Radio 3.5.3.2 C++ API
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00001 /* -*- c++ -*- */ 00002 /* 00003 * Copyright 2002 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 _ATSC_FS_CORRELATOR_NAIVE_H_ 00024 #define _ATSC_FS_CORRELATOR_NAIVE_H_ 00025 00026 #include <atsc_api.h> 00027 #include <atsci_fs_correlator.h> 00028 00029 /*! 00030 * \brief Naive concrete implementation of field sync correlator 00031 */ 00032 class ATSC_API atsci_fs_correlator_naive : public atsci_fs_correlator { 00033 00034 private: 00035 static const int SRSIZE = 1024; // must be power of two 00036 int d_index; // points at oldest sample 00037 float d_sample_sr[SRSIZE]; // sample shift register 00038 unsigned char d_bit_sr[SRSIZE]; // binary decision shift register 00039 00040 static const int OFFSET_511 = 0; // offset to PN 511 pattern 00041 static const int LENGTH_511 = 511 + 4; // length of PN 511 pattern (+ 4 seg sync) 00042 static const int OFFSET_2ND_63 = 578; // offset to second PN 63 pattern 00043 static const int LENGTH_2ND_63 = 63; // length of PN 63 pattern 00044 00045 static unsigned char s_511[LENGTH_511]; // PN 511 pattern 00046 static unsigned char s_63[LENGTH_2ND_63]; // PN 63 pattern 00047 00048 inline static int wrap (int index){ return index & (SRSIZE - 1); } 00049 inline static int incr (int index){ return wrap (index + 1); } 00050 inline static int decr (int index){ return wrap (index - 1); } 00051 00052 public: 00053 00054 // CREATORS 00055 atsci_fs_correlator_naive (); 00056 ~atsci_fs_correlator_naive (); 00057 00058 // MANIPULATORS 00059 virtual void reset (); 00060 void filter (float input_sample, float *output_sample, float *output_tag); 00061 00062 // ACCESSORS 00063 00064 //! return delay in samples from input to output 00065 int delay () const; 00066 00067 }; 00068 00069 00070 #endif /* _ATSC_FS_CORRELATOR_NAIVE_H_ */