annotate filter/gamma_tone.c @ 0:5242703e91d3 tip

Initial checkin for AIM92 aimR8.2 (last updated May 1997).

/*
    Copyright (c) Applied Psychology Unit, Medical Research Council. 1988, 1989
    ===========================================================================

    Permission to use, copy, modify, and distribute this software without fee 
    is hereby granted for research purposes, provided that this copyright 
    notice appears in all copies and in all supporting documentation, and that 
    the software is not redistributed for any fee (except for a nominal shipping 
    charge). Anyone wanting to incorporate all or part of this software in a
    commercial product must obtain a license from the Medical Research Council.

    The MRC makes no representations about the suitability of this 
    software for any purpose.  It is provided "as is" without express or implied 
    warranty.
 
    THE MRC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING 
    ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL THE
    A.P.U. BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY 
    DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN 
    AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

/*

     ====================================================================
      gamma_tone.c - backward compatable interface to new filter release
     ====================================================================

		   J. Holdsworth - 28th January 1989.


    Copywright (c) Applied Psychology Unit, Medical Research Council. 1989.
    =======================================================================


    Release 2:  5th July 1988.
    Release 3: 20th September 1988.
    Release 4: 28th January 1989.

*/

#include  <math.h>

#ifndef   _STITCH_H_
#include  "stitch.h"
#endif
#ifndef   _GAMMA_TONE_H_
#include  "gamma_tone.h"
#endif
#ifndef   _FORMULAE_H_
#include  "formulae.h"
#endif
#ifndef   _RECURSE_H_
#include  "recurse.h"
#endif
#ifndef   _SCALES_H_
#include  "scales.h"
#endif
#ifndef   _PHASE_H_
#include  "phase.h"
#endif

/* identify object file */

#ifndef lint
static char *gt_object_ident = GT_IDENT_STRING ;
#endif


/* base center frequency */

#define   Pi                 ( 3.1415926535 )
#define   TwoPi              ( 2*Pi )

double bankBaseFrequency   = 1000. ;
double filterDefaultGain   = 4.    ;
int filterDefaultInputBits = bits_significant ;


/* generate array of filter center frequencies between the frequencies specified */

double *GenerateCenterFrequencies( min_cf, max_cf, erb_density )
double min_cf, max_cf, erb_density ;
{
    return ( GenerateScale( ErbScale( min_cf ), ErbScale( max_cf ), erb_density, ErbScale( bankBaseFrequency ), FofErbScale ) ) ;
}

int NumberCenterFrequencies( min_cf, max_cf, erb_density )
double min_cf, max_cf, erb_density ;
{
    return ( NumberOnScale( ErbScale( min_cf ), ErbScale( max_cf ), erb_density, ErbScale( bankBaseFrequency ) ) ) ;
}

double *NumberedCenterFrequencies( min_cf, max_cf, channels )
double min_cf, max_cf ;
int channels ;
{
    return ( NumberedScale( ErbScale( min_cf ), ErbScale( max_cf ), channels, FofErbScale ) ) ;
}

/* initialise gamma tone filter code */

FilterBankInfo *InitGammaToneFilterBank( samplerate, order, b_scalar, phase_comp, min_filter_cf )
double samplerate ;
int order ;
double b_scalar ;
int phase_comp ;
double min_filter_cf ;
{
    DeclareNew( FilterBankInfo *, filter_info ) ;
    extern int n_using_sin_table ;

    filter_info->samplerate = samplerate ;
    filter_info->order      = order ;
    filter_info->b_scalar   = b_scalar ;
    filter_info->phase_comp = phase_comp ;

    /* store maximum required time shift for whole filter bank */
    /* originally time advance was implemented as delay of     */
    /* maximum advance minus desired advance (still supported) */

    if( filter_info->phase_comp >= 0 )
	filter_info->max_desired_advance_time = 1. / min_filter_cf * filter_info->phase_comp ;
    else
	filter_info->max_desired_advance_time = ( filter_info->order - 1. ) / ( TwoPi * filter_info->b_scalar * Erb( min_filter_cf ) ) ;

    return ( filter_info ) ;
}

FilterChannelInfo *InitGammaToneFilterChannel( filter_info, cf )
FilterBankInfo *filter_info ;
double cf ;
{
    RecursiveFilterState *filter_state ;
    double sample_delay ;

    if( filter_info->phase_comp > 0 || filter_info->phase_comp == ENVELOPE_ALIGNMENT || filter_info->phase_comp == FINE_ALIGNMENT )
	sample_delay = filter_info->max_desired_advance_time * filter_info->samplerate ;
    else
	sample_delay = 0. ;

    filter_state = NewRecursiveFilter(
		       filter_info->samplerate,
		       cf,
		       Erb( cf ) * filter_info->b_scalar,
		       filterDefaultGain,
		       filter_info->order,
		       filter_info->phase_comp,
		       filterDefaultInputBits,
		       & sample_delay ) ;

    return( ( FilterChannelInfo * ) NewPhaseCompensator(
				       ( FilterState ) filter_state,
				       ( FilterModule ) 0,
				       sample_delay ) ) ;
}

/* end processing of channel - free state varibales */

void EndChannel( channel_info )
FilterChannelInfo *channel_info ;
{
    FreeCompensatedFilter( ( PhaseCompensatorState * ) channel_info ) ;

    return ;
}

/* free up filter state variables and sin table if finished with it */

void EndFilter( filter_info )
FilterBankInfo *filter_info ;
{
    Delete( filter_info ) ;

    return ;
}