62 lines
1.5 KiB
C++
62 lines
1.5 KiB
C++
/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
|
|
|
|
/*
|
|
QM DSP library
|
|
Centre for Digital Music, Queen Mary, University of London.
|
|
|
|
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. See the file
|
|
COPYING included with this distribution for more information.
|
|
*/
|
|
|
|
#ifndef SINC_WINDOW_H
|
|
#define SINC_WINDOW_H
|
|
|
|
#include <vector>
|
|
|
|
/**
|
|
* A window containing values of the sinc function, i.e. sin(x)/x with
|
|
* sinc(0) == 1, with x == 0 at the centre.
|
|
*/
|
|
class SincWindow
|
|
{
|
|
public:
|
|
/**
|
|
* Construct a windower of the given length, containing the values
|
|
* of sinc(x) with x=0 in the middle, i.e. at sample (length-1)/2
|
|
* for odd or (length/2)+1 for even length, such that the distance
|
|
* from -pi to pi (the nearest zero crossings either side of the
|
|
* peak) is p samples.
|
|
*/
|
|
SincWindow(int length, double p) : m_length(length), m_p(p) { init(); }
|
|
|
|
int getLength() const {
|
|
return m_length;
|
|
}
|
|
|
|
const double *getWindow() const {
|
|
return &m_window[0];
|
|
}
|
|
|
|
void cut(double *src) const {
|
|
cut(src, src);
|
|
}
|
|
|
|
void cut(const double *src, double *dst) const {
|
|
for (int i = 0; i < m_length; ++i) {
|
|
dst[i] = src[i] * m_window[i];
|
|
}
|
|
}
|
|
|
|
private:
|
|
int m_length;
|
|
double m_p;
|
|
std::vector<double> m_window;
|
|
|
|
void init();
|
|
};
|
|
|
|
#endif
|