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
114
115
116
117
118
119
120
121
122
123
|
/*
* Copyright (C) 2002-2004 by Jonathan Naylor G4KLX
*
* 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 2 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <cmath>
using namespace std;
#include "SFFT.h"
#include "Inline.h"
#include <wx/object.h> // Not sure why !
#include <wx/debug.h>
const double STABCOEFF = 0.9999;
CSFFT::CSFFT(int len, int first, int last) :
m_fftLen(len),
m_first(first),
m_last(last),
m_ptr(0)
{
wxASSERT(m_fftLen > 0);
wxASSERT(m_first > 0);
wxASSERT(m_last > first);
m_cos = new double[m_fftLen];
m_sin = new double[m_fftLen];
m_history = new complex<double>[m_fftLen];
m_bins = new complex<double>[m_fftLen];
for (int i = 0; i < m_fftLen; i++) {
double val = double(i) * 2.0 * M_PI / double(m_fftLen);
m_cos[i] = ::cos(val) * STABCOEFF;
m_sin[i] = ::sin(val) * STABCOEFF;
m_history[i] = complex<double>(0.0, 0.0);
m_bins[i] = complex<double>(0.0, 0.0);
}
m_corr = ::pow(STABCOEFF, double(m_fftLen));
}
CSFFT::~CSFFT()
{
delete[] m_cos;
delete[] m_sin;
delete[] m_history;
delete[] m_bins;
}
/*
* Sliding FFT
*/
void CSFFT::process(double in, double* bins)
{
wxASSERT(bins != NULL);
/* restore the sample fftlen samples back */
complex<double> old = m_history[m_ptr] * m_corr;
/* save the new sample */
m_history[m_ptr] = complex<double>(in, 0.0);
/* advance the history pointer */
m_ptr = (m_ptr + 1) % m_fftLen;
/* calculate the wanted bins */
for (int i = m_first; i < m_last; i++) {
complex<double> z = m_bins[i];
z -= old;
z += in;
double real = z.real() * m_cos[i] - z.imag() * m_sin[i];
double imag = z.real() * m_sin[i] + z.imag() * m_cos[i];
m_bins[i] = complex<double>(real, imag);
bins[i] = ::CABS(m_bins[i]);
}
}
void CSFFT::process(double in, complex<double>* bins)
{
wxASSERT(bins != NULL);
/* restore the sample fftlen samples back */
complex<double> old = m_history[m_ptr] * m_corr;
/* save the new sample */
m_history[m_ptr] = complex<double>(in, 0.0);
/* advance the history pointer */
m_ptr = (m_ptr + 1) % m_fftLen;
/* calculate the wanted bins */
for (int i = m_first; i < m_last; i++) {
complex<double> z = m_bins[i];
z -= old;
z += in;
double real = z.real() * m_cos[i] - z.imag() * m_sin[i];
double imag = z.real() * m_sin[i] + z.imag() * m_cos[i];
bins[i] = m_bins[i] = complex<double>(real, imag);
}
}
|
