fir.h

/***************************************************************************
        Copyright (C) 2002-2015 Kentaro Kitagawa
                           kitagawa@phys.s.u-tokyo.ac.jp
        
        This program is free software; you can redistribute it and/or
        modify it under the terms of the GNU Library General Public
        License as published by the Free Software Foundation; either
        version 2 of the License, or (at your option) any later version.
        
        You should have received a copy of the GNU Library General 
        Public License and a list of authors along with this program; 
        see the files COPYING and AUTHORS.
***************************************************************************/
/*
  Finite Impulse Response Filter
*/


#ifndef FIR_H
#define FIR_H

#include "support.h"
#include <vector>
#include <complex>
#include <fftw3.h>

//! FIR (Finite Impulse Response) Digital Filter.
//! Accelerated by FFT.
class DECLSPEC_KAME FIR {
public:
    //! makes coeff. for BPF. Window func. method.
    //! \param taps odd num. a number of taps
    //! \param bandwidth 0 to 1.0. the unit is sampling freq.
    //! \param center 0.0 to 1.0. the unit is sampling freq.
    FIR(int taps, double bandwidth, double center);
    ~FIR();
    void exec(const double *src, double *dst, int len);
    int taps() const {return m_taps;}
    double bandWidth() const {return m_bandWidth;}
    double centerFreq() const {return m_centerFreq;}
private:
    fftw_plan m_rdftplan, m_ridftplan;
    double *m_pBufR;
    fftw_complex *m_pBufC;
    std::vector<double> m_firWnd;
    int m_fftLen, m_tapLen;
    const int m_taps;
    const double m_bandWidth;
    const double m_centerFreq;
};

#endif //FIR_H