GNU Radio Manual and C++ API Reference 3.7.14.0
The Free & Open Software Radio Ecosystem
slicer_agc_impl.h
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1/* -*- c++ -*- */
2/*
3 * Copyright 2002 Free Software Foundation, Inc.
4 *
5 * This file is part of GNU Radio
6 *
7 * GNU Radio is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
10 * any later version.
11 *
12 * GNU Radio is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
21 */
22
23#ifndef _ATSC_SLICER_AGC_H_
24#define _ATSC_SLICER_AGC_H_
25
26#include <gnuradio/atsc/api.h>
28#include <math.h>
29
30/*!
31 * \brief Automatic Gain Control class for atsc slicer
32 *
33 * Given perfect data, output values will be +/- {7, 5, 3, 1}
34 */
35
37{
38
39public:
40 atsci_slicer_agc() : _gain(1), dc(0.0025){};
41
42
43 float gain() { return _gain; }
44
45#if 1
46 float scale(float input)
47 {
48 float t = input * _gain;
49 float output = t - REFERENCE;
50 float error = REFERENCE - dc.filter(t);
51 _gain += error * RATE;
52 return output;
53 }
54#else
55 float scale(float input)
56 {
57 float avg = dc.filter(input);
58 if (fabs(avg) < .1)
59 avg = .1;
60 _gain += _gain * .99 + .01 * REFERENCE / avg;
61 return input * _gain - REFERENCE;
62 }
63#endif
64
65protected:
66 static const float REFERENCE = 1.25; // pilot reference value
67 static const float RATE = 1.0e-5; // adjustment rate
68 float _gain; // current gain
70};
71
72#endif /* _ATSC_SLICER_AGC_H_ */
Automatic Gain Control class for atsc slicer.
Definition: slicer_agc_impl.h:37
gr::filter::single_pole_iir< float, float, float > dc
Definition: slicer_agc_impl.h:69
float _gain
Definition: slicer_agc_impl.h:68
float scale(float input)
Definition: slicer_agc_impl.h:46
atsci_slicer_agc()
Definition: slicer_agc_impl.h:40
float gain()
Definition: slicer_agc_impl.h:43
#define ATSC_API
Definition: gr-atsc/include/gnuradio/atsc/api.h:30