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
|
/* -*- c++ -*- */
/*
* Copyright 2004,2011,2012 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifndef INCLUDED_DIGITAL_CLOCK_RECOVERY_MM_FF_H
#define INCLUDED_DIGITAL_CLOCK_RECOVERY_MM_FF_H
#include <gnuradio/block.h>
#include <gnuradio/digital/api.h>
namespace gr {
namespace digital {
/*!
* \brief Mueller and Müller (M&M) based clock recovery block with float input, float
* output. \ingroup synchronizers_blk
*
* \details
* This implements the Mueller and Müller (M&M) discrete-time
* error-tracking synchronizer.
*
* The peak to peak input signal amplitude must be symmetrical
* about zero, as the M&M timing error detector (TED) is a
* decision directed TED, and this block uses a symbol decision
* slicer referenced at zero.
*
* The input signal peak amplitude should be controlled to a
* consistent level (e.g. +/- 1.0) before this block to achieve
* consistent results for given gain settings; as the TED's output
* error signal is directly affected by the input amplitude.
*
* The input signal must have peaks in order for the TED to output
* a correct error signal. If the input signal pulses do not have
* peaks (e.g. rectangular pulses) the input signal should be
* conditioned with a matched pulse filter or other appropriate
* filter to peak the input pulses. For a rectangular base pulse
* that is N samples wide, the matched filter taps would be
* [1.0/float(N)]*N, or in other words a moving average over N
* samples.
*
* This block will output samples at a rate of one sample per
* recovered symbol, and is thus not outputting at a constant rate.
*
* Output symbols are not a subset of input, but may be interpolated.
*
* See "Digital Communication Receivers: Synchronization, Channel
* Estimation and Signal Processing" by Heinrich Meyr, Marc
* Moeneclaey, & Stefan Fechtel. ISBN 0-471-50275-8.
*/
class DIGITAL_API clock_recovery_mm_ff : virtual public block
{
public:
// gr::digital::clock_recovery_mm_ff::sptr
typedef std::shared_ptr<clock_recovery_mm_ff> sptr;
/*!
* Make a M&M clock recovery block.
*
* \param omega Initial estimate of samples per symbol
* \param gain_omega Gain setting for omega update loop
* \param mu Initial estimate of phase of sample
* \param gain_mu Gain setting for mu update loop
* \param omega_relative_limit maximum relative deviation from omega
*/
static sptr make(float omega,
float gain_omega,
float mu,
float gain_mu,
float omega_relative_limit);
virtual float mu() const = 0;
virtual float omega() const = 0;
virtual float gain_mu() const = 0;
virtual float gain_omega() const = 0;
virtual void set_verbose(bool verbose) = 0;
virtual void set_gain_mu(float gain_mu) = 0;
virtual void set_gain_omega(float gain_omega) = 0;
virtual void set_mu(float mu) = 0;
virtual void set_omega(float omega) = 0;
};
} /* namespace digital */
} /* namespace gr */
#endif /* INCLUDED_DIGITAL_CLOCK_RECOVERY_MM_FF_H */
|
