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
101
102
103
104
105
106
107
108
109
110
111
112
113
|
/*
dsp/Sine.h
Copyright 2003-14 Tim Goetze <tim@quitte.de>
http://quitte.de/dsp/
Direct form I recursive sin() generator. Utilising doubles
for stability.
*/
/*
This program 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 3
of the License, or (at your option) any later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA or point your web browser to http://www.gnu.org.
*/
#ifndef DSP_SINE_H
#define DSP_SINE_H
namespace DSP {
class Sine
{
public:
int z;
double y[2];
double b;
public:
Sine()
{
b = 0;
y[0] = y[1] = 0;
z = 0;
}
Sine (double f, double fs, double phase)
{
set_f (f, fs, phase);
}
Sine (double w, double phase = 0.)
{
set_f (w, phase);
}
inline void set_f (double f, double fs, double phase)
{
set_f (f*2*M_PI/fs, phase);
}
inline void set_f (double w, double phase)
{
b = 2*cos(w);
y[0] = sin (phase - w);
y[1] = sin (phase - 2*w);
z = 0;
}
/* advance and return 1 sample */
inline double get()
{
double s = b*y[z];
z ^= 1;
s -= y[z];
return y[z] = s;
}
double get_phase()
{
double x0 = y[z], x1 = b*y[z] - y[z^1];
double phi = asin(x0);
/* slope is falling: into the 2nd half. */
return x1 < x0 ? M_PI - phi : phi;
}
};
/* same as above but including a damping coefficient d */
class DampedSine
: public Sine
{
public:
double d;
public:
DampedSine()
{ d = 1; }
inline double get()
{
double s = b * y[z];
z ^= 1;
s -= d * y[z];
return y[z] = d * s;
}
};
} /* namespace DSP */
#endif /* DSP_SINE_H */
|
