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/* -*- 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 file 2005-2006 Christian Landone.
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.
*/
#include "PhaseVocoder.h"
#include "dsp/transforms/FFT.h"
#include <math.h>
//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////
PhaseVocoder::PhaseVocoder(unsigned int n) :
m_n(n)
{
m_fft = new FFTReal(m_n);
m_realOut = new double[m_n];
m_imagOut = new double[m_n];
}
PhaseVocoder::~PhaseVocoder()
{
delete [] m_realOut;
delete [] m_imagOut;
delete m_fft;
}
void PhaseVocoder::FFTShift(unsigned int size, double *src)
{
const int hs = size/2;
for (int i = 0; i < hs; ++i) {
double tmp = src[i];
src[i] = src[i + hs];
src[i + hs] = tmp;
}
}
void PhaseVocoder::process(double *src, double *mag, double *theta)
{
FFTShift( m_n, src);
m_fft->process(0, src, m_realOut, m_imagOut);
getMagnitude( m_n/2, mag, m_realOut, m_imagOut);
getPhase( m_n/2, theta, m_realOut, m_imagOut);
}
void PhaseVocoder::getMagnitude(unsigned int size, double *mag, double *real, double *imag)
{
unsigned int j;
for( j = 0; j < size; j++)
{
mag[ j ] = sqrt( real[ j ] * real[ j ] + imag[ j ] * imag[ j ]);
}
}
void PhaseVocoder::getPhase(unsigned int size, double *theta, double *real, double *imag)
{
unsigned int k;
// Phase Angle "matlab" style
//Watch out for quadrant mapping !!!
for( k = 0; k < size; k++)
{
theta[ k ] = atan2( -imag[ k ], real[ k ]);
}
}
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