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