GETFilterLow2.hh

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//======================================================================
/*! \file GETFilterLow2.hh
 *
 *  Include file for the GETFilterLow2 class.
 */
//======================================================================

#ifndef GET_FILTER_LOW2_HH
#define GET_FILTER_LOW2_HH

//----------------------------------------------------------------------

#include "GETFilterCut.hh"

//======================================================================
/*! \class GETFilterLow2
 *
 *  This class defines a low pass filter of order 2, with a response
 *  in Fourier space with following form:
 *    \f[
          F(f) = \frac{1}{1 - \left( \frac{f}{f_{0}} \right)^{2}
                            + j \frac{1}{Q} \frac{f}{f_{0}}}
 *    \f]
 *  where \f$ f_{0} \f$ is the cut frequency and \f$ Q \f$ is the
 *  quality factor:
 *  - if \f$ Q = 0.5 \f$, the filter corresponds to the successive application
 *    of two first order filters;
 *  - if \f$ Q > 0.5 \sqrt{2} \f$ the filter has a pseudo-resonance.
 */
class GETFilterLow2 : public GETFilterCut
{
  //------------------------------------------------------------
  /*! \object_doc */
  GObject(GETFilterLow2);
  //------------------------------------------------------------

  protected:

    double    quality_factor;     ///< Quality factor of the filter

  public:
  //----------------------------------------------------------
  /** @name Constructors, affectation, destructor */
  //@{
    GETFilterLow2 ( u_int n = 0, double dt = 0.01L,
                    double fcut = 0.L, double q = 0.7071067811865475244008443621048490L );
    GETFilterLow2 ( const GETFilterLow2 & proc );
    virtual ~GETFilterLow2 ( );
  //@}


  //----------------------------------------------------------
  /** @name Initialization functions */
  //@{
    virtual void  SetQualityFactor ( double q );
    double        GetQualityFactor ( ) const;   // inline

    virtual void  UpdateFilter ( );
  //@}

  //----------------------------------------------------------
  /** @name ROOT related functions */
  //@{
  public:

    /*! for use within ROOT.*/
    ClassDef(GETFilterLow2,0);
  //@}
};


//----------------------------------------------------------------------
//  Inline functions
#include "icc/GETFilterLow2.icc"


//======================================================================
#endif