blob: 505a2e296d6dae5829f5db6ebbef9f5879e025a9 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
|
/* -*- c++ -*- */
/*
* Copyright 2004,2013 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifndef INCLUDED_GR_SIMPLE_CORRELATOR_IMPL_H
#define INCLUDED_GR_SIMPLE_CORRELATOR_IMPL_H
#include <gnuradio/digital/simple_correlator.h>
//#define DEBUG_SIMPLE_CORRELATOR
namespace gr {
namespace digital {
class simple_correlator_impl : public simple_correlator
{
private:
static constexpr int OVERSAMPLE = 8;
enum state_t { ST_LOOKING, ST_UNDER_THRESHOLD, ST_LOCKED };
int d_payload_bytesize;
state_t d_state;
unsigned int d_osi; // over sample index [0,OVERSAMPLE-1]
unsigned int d_transition_osi; // first index where Hamming dist < thresh
unsigned int d_center_osi; // center of bit
unsigned long long int d_shift_reg[OVERSAMPLE];
int d_bblen; // length of bitbuf
unsigned char* d_bitbuf; // demodulated bits
unsigned char* d_pktbuf; // temp packet buf
int d_bbi; // bitbuf index
static const int AVG_PERIOD = 512; // must be power of 2 (for freq offset correction)
int d_avbi;
float d_avgbuf[AVG_PERIOD];
float d_avg;
float d_accum;
#ifdef DEBUG_SIMPLE_CORRELATOR
FILE* d_debug_fp; // binary log file
#endif
inline int slice(float x) { return x >= d_avg ? 1 : 0; }
void update_avg(float x);
void enter_locked();
void enter_under_threshold();
void enter_looking();
static int add_index(int a, int b)
{
int t = a + b;
if (t >= OVERSAMPLE)
t -= OVERSAMPLE;
assert(t >= 0 && t < OVERSAMPLE);
return t;
}
static int sub_index(int a, int b)
{
int t = a - b;
if (t < 0)
t += OVERSAMPLE;
assert(t >= 0 && t < OVERSAMPLE);
return t;
}
public:
simple_correlator_impl(int payload_bytesize);
~simple_correlator_impl() override;
int general_work(int noutput_items,
gr_vector_int& ninput_items,
gr_vector_const_void_star& input_items,
gr_vector_void_star& output_items) override;
};
} /* namespace digital */
} /* namespace gr */
#endif /* INCLUDED_GR_SIMPLE_CORRELATOR_IMPL_H */
|
