3 * Copyright 2002 Free Software Foundation, Inc.
5 * This file is part of GNU Radio
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23 #ifndef _ATSC_FS_CORRELATOR_NAIVE_H_
24 #define _ATSC_FS_CORRELATOR_NAIVE_H_
26 #include <atsci_fs_correlator.h>
29 * \brief Naive concrete implementation of field sync correlator
31 class atsci_fs_correlator_naive : public atsci_fs_correlator {
34 static const int SRSIZE = 1024; // must be power of two
35 int d_index; // points at oldest sample
36 float d_sample_sr[SRSIZE]; // sample shift register
37 unsigned char d_bit_sr[SRSIZE]; // binary decision shift register
39 static const int OFFSET_511 = 0; // offset to PN 511 pattern
40 static const int LENGTH_511 = 511 + 4; // length of PN 511 pattern (+ 4 seg sync)
41 static const int OFFSET_2ND_63 = 578; // offset to second PN 63 pattern
42 static const int LENGTH_2ND_63 = 63; // length of PN 63 pattern
44 static unsigned char s_511[LENGTH_511]; // PN 511 pattern
45 static unsigned char s_63[LENGTH_2ND_63]; // PN 63 pattern
47 inline static int wrap (int index){ return index & (SRSIZE - 1); }
48 inline static int incr (int index){ return wrap (index + 1); }
49 inline static int decr (int index){ return wrap (index - 1); }
54 atsci_fs_correlator_naive ();
55 ~atsci_fs_correlator_naive ();
58 virtual void reset ();
59 void filter (float input_sample, float *output_sample, float *output_tag);
63 //! return delay in samples from input to output
69 #endif /* _ATSC_FS_CORRELATOR_NAIVE_H_ */