fft.h

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/***************************************************************************
                          fft.h  -  description
                             -------------------
    begin                : Mon Jul 1 2002
    copyright            : (C) 2002 by Peter Haase
    email                : mail@p-haase.de
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This library is free software; you can redistribute it and/or         *
 *   modify it under the terms of the GNU Lesser General Public            *
 *   License as published by the Free Software Foundation; either          *
 *   version 2.1 of the License, or (at your option) any later version.    *
 *                                                                         *
 *   This library 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     *
 *   Lesser General Public License for more details.                       *
 *                                                                         *
 *   You should have received a copy of the GNU Lesser General Public      *
 *   License along with this library; if not, write to the Free Software   *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 *                                                                         *
 ***************************************************************************/
#ifndef FFT_MYHEADER
#define FFT_MYHEADER

#include <stdexcept>
#include <vector>

#include "phbib.h"
#include "signals.h"
#include "misc.h"



namespace simthlib
{

using simth::Complex;

//--------------------------------------------------------------------
//
// class FastFourierTrans
//
//
//   Konstruktoren
//     FastFourierTrans():  einmalige Erstellung des Sinus-Arrays
//
//   Funktionen
//     sinus_array():  Zeiger auf Feld mit Sinuswerten zurueckgeben
//     Transform(Sequence &inseq, Sequence* &outseq,
//   int space, int fac, flag_FFT isign) :
//               inseq: Eingangssequence
//              outseq: Ausgangssequence
//                 space: Abtastschrittweite
//                 fac: Oversamplingfaktor
//               isign: Flag fuer FFT (-1) bzw. IFFT (1)
//     FFT und IFFT : siehe Transformation ohne isign-Flag
//
//--------------------------------------------------------------------

class FastFourierTrans
{

  public:

    enum FFT_type {FT = -1, IFT = 1};


    FastFourierTrans() : MAX_FFT_LEN(4096) { MakeSinusArray(); }

    ~FastFourierTrans() { delete [] sinus; }

    void FFT(const simth::Array<Complex> &inseq,
             simth::Array<Complex>* outseq, int space, int fac) const;

    void IFFT(const simth::Array<Complex> &inseq,
              simth::Array<Complex>* outseq, int space, int fac) const;

  private:

    double *sinus;

    const int MAX_FFT_LEN;

    void MakeSinusArray(void);

    int GetNewLength(int len, int space, int fac) const;

    void Transform(const simth::Array<Complex> &inseq,
                   simth::Array<Complex> *outseq,
                   int space, int fac, FFT_type isign) const;



};



}



#endif

---