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
|
/* -*- c++ -*- */
/*
* Copyright 2011,2012 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifndef INCLUDED_DIGITAL_KURTOTIC_EQUALIZER_CC_IMPL_H
#define INCLUDED_DIGITAL_KURTOTIC_EQUALIZER_CC_IMPL_H
#include <gnuradio/digital/kurtotic_equalizer_cc.h>
#include <gnuradio/filter/fir_filter.h>
#include <gnuradio/math.h>
#include <complex>
#include <stdexcept>
namespace gr {
namespace digital {
class kurtotic_equalizer_cc_impl : public kurtotic_equalizer_cc,
filter::kernel::fir_filter_ccc
{
private:
std::vector<gr_complex> d_new_taps;
gr_complex d_error;
float d_mu;
float d_p, d_m;
gr_complex d_q, d_u;
float d_alpha_p, d_alpha_q, d_alpha_m;
gr_complex sign(gr_complex x)
{
float re = (float)(x.real() >= 0.0f);
float im = (float)(x.imag() >= 0.0f);
return gr_complex(re, im);
}
protected:
virtual gr_complex error(const gr_complex& out)
{
// p = E[|z|^2]
// q = E[z^2]
// m = E[|z|^4]
// u = E[kurtosis(z)]
float nrm = std::norm(out);
gr_complex cnj = std::conj(out);
float epsilon_f = 1e-12;
gr_complex epsilon_c = gr_complex(1e-12, 1e-12);
d_p = (1 - d_alpha_p) * d_p + (d_alpha_p)*nrm + epsilon_f;
d_q = (1 - d_alpha_q) * d_q + (d_alpha_q)*out * out + epsilon_c;
d_m = (1 - d_alpha_m) * d_m + (d_alpha_m)*nrm * nrm + epsilon_f;
d_u = d_m - 2.0f * (d_p * d_p) - d_q * d_q;
gr_complex F =
(1.0f / (d_p * d_p * d_p)) *
(sign(d_u) * (nrm * cnj - 2.0f * d_p * cnj - std::conj(d_q) * out) -
std::abs(d_u) * cnj);
float re = gr::clip(F.real(), 1.0);
float im = gr::clip(F.imag(), 1.0);
return gr_complex(re, im);
}
virtual void update_tap(gr_complex& tap, const gr_complex& in)
{
tap += d_mu * in * d_error;
}
public:
kurtotic_equalizer_cc_impl(int num_taps, float mu);
~kurtotic_equalizer_cc_impl();
float gain() const { return d_mu; }
void set_gain(float mu)
{
if (mu < 0)
throw std::out_of_range(
"kurtotic_equalizer_cc_impl::set_gain: Gain value must be >= 0");
d_mu = mu;
}
int work(int noutput_items,
gr_vector_const_void_star& input_items,
gr_vector_void_star& output_items) override;
};
} /* namespace digital */
} /* namespace gr */
#endif /* INCLUDED_DIGITAL_KURTOTIC_EQUALIZER_CC_IMPL_H */
|
