Dedispersion.h

//-*-C++-*-
/***************************************************************************
 *
 *   Copyright (C) 2002 - 2020 by Willem van Straten
 *   Licensed under the Academic Free License version 2.1
 *
 ***************************************************************************/
 
// dspsr/Signal/General/dsp/Dedispersion.h
 
#ifndef __Dedispersion_h
#define __Dedispersion_h
 
#include "dsp/PlasmaResponse.h"
 
class ThreadContext;
 
namespace dsp {
 
  /* This class implements the phase-coherent dedispersion kernel, as
     determined by the frequency response of the interstellar
     medium. */
 
  class Dedispersion : public PlasmaResponse 
  {
 
  public:
 
    static const double dm_dispersion;
 
    Dedispersion();
 
    ~Dedispersion();
 
    void prepare (const Observation* input, unsigned channels);
 
    virtual void mark (Observation* output);
 
    void set_dispersion_measure (double dm);
 
    double get_dispersion_measure () const { return dispersion_measure; }
 
    double delay_time (double freq) const override;
 
    class SampleDelay;
 
    void set_sample_delay (SampleDelay*);
 
    SampleDelay* get_sample_delay ();
 
    virtual void build (const Observation* input = 0);
 
    void build (std::vector<float>& phases, unsigned npts, unsigned nchan);
 
    void set_build_delays (bool delay = true);
 
  protected:
 
    double dispersion_measure = 0.0;
 
    Reference::To<SampleDelay> sample_delay;
 
    bool build_delays = false;
 
    void build (unsigned ndat, unsigned nchan);
 
    friend class PlasmaResponse;
 
    void build_setup (double chan_freq);
    double interchannel_fractional_sample_delay = 0.0;
 
    double build_compute (double chan_freq, double freq);
  };
 
}
 
#endif