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
88
89
90
91
92
93
94
95
96
97
98
99
100
|
/*
* Copyright 2004,2006 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* GNU Radio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <pager_slicer_fb.h>
#include <gr_io_signature.h>
pager_slicer_fb_sptr pager_make_slicer_fb(float alpha, float beta)
{
return pager_slicer_fb_sptr(new pager_slicer_fb(alpha, beta));
}
pager_slicer_fb::pager_slicer_fb(float alpha, float beta) :
gr_sync_block ("slicer_fb",
gr_make_io_signature (1, 1, sizeof(float)),
gr_make_io_signature (1, 1, sizeof(unsigned char)))
{
d_alpha = alpha;
d_beta = beta;
d_max = 0.0;
d_hi = 0.0;
d_avg = 0.0;
d_lo = 0.0;
d_min = 0.0;
}
// Tracks average, minimum, and peak, then converts input into one of:
//
// [0, 1, 2, 3]
unsigned char pager_slicer_fb::slice(float sample)
{
unsigned char decision;
// Update DC level and remove
d_avg = d_avg*(1.0-d_alpha)+sample*d_alpha;
sample -= d_avg;
if (sample > 0) {
if (sample > d_hi) { // In max region
d_max = d_max*(1.0-d_alpha) + sample*d_alpha;
decision = 3;
}
else {
d_max -= (d_max-d_avg)*d_beta; // decay otherwise
decision = 2;
}
}
else {
if (sample < d_lo) { // In min region
d_min = d_min*(1.0-d_alpha) + sample*d_alpha;
decision = 0;
}
else {
d_min -= (d_min-d_avg)*d_beta; // decay otherwise
decision = 1;
}
}
d_hi = d_max*2.0/3.0;
d_lo = d_min*2.0/3.0;
//fprintf(stderr, "%f %d\n", sample, decision);
return decision;
}
int pager_slicer_fb::work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
float *iptr = (float *) input_items[0];
unsigned char *optr = (unsigned char *) output_items[0];
int size = noutput_items;
for (int i = 0; i < size; i++)
*optr++ = slice(*iptr++);
return noutput_items;
}
|
