Filterbank.h

//-*-C++-*-
/***************************************************************************
 *
 *   Copyright (C) 2002-2011 by Willem van Straten
 *   Licensed under the Academic Free License version 2.1
 *
 ***************************************************************************/
 
// dspsr/Signal/General/dsp/Filterbank.h
 
#ifndef __Filterbank_h
#define __Filterbank_h
 
#include "dsp/Convolution.h"
 
namespace dsp {
 
  /* This class implements the coherent filterbank technique described
     in Willem van Straten's thesis.  */
 
  class Filterbank: public Convolution {
 
  public:
 
    class Config;
 
    Filterbank (const char* name = "Filterbank", Behaviour type = outofplace);
 
    void prepare ();
 
    void reserve ();
 
    uint64_t bytes_storage() const override;
 
    uint64_t bytes_scratch () const override;
 
    uint64_t get_minimum_samples () { return nsamp_fft; }
 
    uint64_t get_minimum_samples_lost () { return nsamp_overlap; }
 
    void set_nchan (unsigned _nchan) { nchan = _nchan; }
 
    unsigned get_nchan () const { return nchan; }
 
    unsigned get_nchan_subband () const {return nchan_subband; }
 
    void set_freq_res (unsigned _freq_res) { freq_res = _freq_res; }
    void set_frequency_resolution (unsigned fres) { freq_res = fres; }
 
    unsigned get_freq_res () const { return freq_res; }
    unsigned get_frequency_resolution () const { return freq_res; }
 
    void set_frequency_overlap (unsigned over) { overlap_ratio = over; }
    unsigned get_frequency_overlap () const { return (unsigned) overlap_ratio; }
 
    unsigned get_nfilt_pos() {return nfilt_pos;}
 
    unsigned get_nfilt_neg() {return nfilt_neg;}
 
    FTransform::Plan* get_forward();
 
    FTransform::Plan* get_backward();
 
    class Engine;
    void set_engine (Engine*);
    Engine* get_engine();
 
  protected:
 
    virtual void transformation ();
 
    virtual void filterbank ();
    virtual void custom_prepare () {}
 
    unsigned nchan;
 
    unsigned freq_res;
 
    // This is the number of channels each input channel will be divided into
    unsigned nchan_subband;
 
    double overlap_ratio;
 
    Reference::To<Engine> engine;
 
    Reference::To<ScalarFilter> zero_DM_normalizer;
 
  private:
 
    void do_prepare ();
    void prepare_output (uint64_t ndat = 0, bool set_ndat = false);
    void resize_output (bool reserve_extra = false);
 
  };
 
}
 
#endif