tomwalters@0: /*
tomwalters@0:   step.c    generate a step up or down.
tomwalters@0:   ------
tomwalters@0: 
tomwalters@0: */
tomwalters@0: 
tomwalters@0: #include <stdio.h>
tomwalters@0: #include <math.h>
tomwalters@0: #include "options.h"
tomwalters@0: #include "units.h"
tomwalters@0: #include "strmatch.h"
tomwalters@0: 
tomwalters@0: char applic[]  = "generate a step waveform. " ;
tomwalters@0: char usage[]   = "step [options]" ;
tomwalters@0: 
tomwalters@0: static char *helpstr, *debugstr, *sampstr, *astr,  *dstr, *typestr ;
tomwalters@0: static char *shiftstr, *polstr ;
tomwalters@0: 
tomwalters@0: static Options option[] = {
tomwalters@0:     {   "help"      ,   "off"       ,  &helpstr     ,   "help"                              , DEBUG   },
tomwalters@0:     {   "debug"     ,   "off"       ,  &debugstr    ,   "debugging switch"                  , DEBUG   },
tomwalters@0:     {   "samplerate",   "20kHz"     ,  &sampstr     ,   "samplerate "                       , VAL     },
tomwalters@0:     {   "amplitude" ,   "1"         ,  &astr        ,   "step height"                       , VAL     },
tomwalters@0:     {   "shift"     ,   "10ms"      ,  &shiftstr    ,   "position of step relative to start", VAL     },
tomwalters@0:     {   "polarity"  ,   "up"        ,  &polstr      ,   "step up or down"                   , VAL     },
tomwalters@0:     {   "duration"  ,   "500ms"     ,  &dstr        ,   "duration of waveform"              , VAL     },
tomwalters@0:     {   "type"      ,   "short"     ,  &typestr     ,   "output datatype"                   , VAL     },
tomwalters@0:    ( char * ) 0 } ;
tomwalters@0: 
tomwalters@0: 
tomwalters@0: int     samplerate ;
tomwalters@0: float   amplitude  ;
tomwalters@0: int     duration   ;
tomwalters@0: int     shift      ;
tomwalters@0: int     type       ;
tomwalters@0: 
tomwalters@0: main(argc, argv)
tomwalters@0: int   argc ;
tomwalters@0: char *argv[] ;
tomwalters@0: {
tomwalters@0:     int   i ;
tomwalters@0:     float y0, y1 ;
tomwalters@0: 
tomwalters@0:     getopts( option,argc,argv ) ;
tomwalters@0:     if ( !isoff( helpstr ) )
tomwalters@0: 	helpopts3( helpstr, argv[0], applic, usage, option ) ;
tomwalters@0: 
tomwalters@0:     samplerate = to_Hz( sampstr, 0 ) ;
tomwalters@0:     amplitude  = atof( astr ) ;
tomwalters@0:     shift      = to_p( shiftstr, samplerate ) ;
tomwalters@0:     duration   = to_p( dstr, samplerate ) ;
tomwalters@0: 
tomwalters@0:     if ( ( type = typeindex( typestr ) ) < 0 ) {
tomwalters@0: 	fprintf(stderr,"step: unknown datatype [%s]\n", typestr) ;
tomwalters@0: 	exit( 1 ) ;
tomwalters@0:     }
tomwalters@0: 
tomwalters@0:     if ( isstr( polstr, "up" ) ) {
tomwalters@0: 	y0 = 0 ;         y1 = amplitude ;
tomwalters@0:     }
tomwalters@0:     else if ( isstr( polstr, "down" ) ) {
tomwalters@0: 	y0 = amplitude ; y1 = 0 ;
tomwalters@0:     }
tomwalters@0:     else {
tomwalters@0: 	fprintf(stderr,"step: unknown polarity [%s]\n", polstr) ;
tomwalters@0: 	exit( 1 ) ;
tomwalters@0:     }
tomwalters@0: 
tomwalters@0:     for ( i = 0 ; i < shift ; i++ )
tomwalters@0: 	writeitem( &y0, type, 1, stdout ) ;
tomwalters@0:     for (  ; i < duration ; i++ )
tomwalters@0: 	writeitem( &y1, type, 1, stdout ) ;
tomwalters@0: 
tomwalters@0: }