tomwalters@0: /*
tomwalters@0:   tone.c    generate a pure tone.
tomwalters@0:   ------
tomwalters@0:     Generate samples of a sine wave at a given sample rate.
tomwalters@0:     Specify wave amplitude, and frequency (in Hz or kHz), or alternatively
tomwalters@0:     period (in s, ms, or p (sample points) ). If both period and frequency
tomwalters@0:     are specified, then the given period takes precedence.
tomwalters@0:     If S is the samplerate, and Ts=1/S is the sample interval,
tomwalters@0:     then each sample of a sine wave of period T samples is given by:
tomwalters@0: 	sin(n*(Ts/T)*TWOPI)  for  n=0,1,2,...
tomwalters@0:     Output samples in the given datatype for the given waveform duration.
tomwalters@0: 
tomwalters@0: 
tomwalters@0: Examples:
tomwalters@0: 
tomwalters@0: 1. Sine wave with period 10ms sampled at 10kHz, (100 sample points per period)
tomwalters@0: 
tomwalters@0: tone period=10ms samplerate=10kHz | x11plot
tomwalters@0: 
tomwalters@0: 2. Sine wave with frequency 100Hz sampled at 20kHz
tomwalters@0: 
tomwalters@0: tone frequency=100Hz | x11plot
tomwalters@0: 
tomwalters@0: 3. Sine wave with period 100 sample points, with dc-offset set equal to
tomwalters@0:    amplitude of 500 so that waveform is just non-negative.
tomwalters@0: 
tomwalters@0: tone period=100p amplitude=500 offset=500 | x11plot
tomwalters@0: 
tomwalters@0: 4. Quarter cycle of a sine wave with 8ms period.
tomwalters@0: 
tomwalters@0: tone period=8ms duration=2ms | x11plot
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: #define TWOPI   6.28318530717
tomwalters@0: 
tomwalters@0: char applic[]  = "generate a pure tone. " ;
tomwalters@0: char usage[]   = "tone [options]" ;
tomwalters@0: 
tomwalters@0: static char *helpstr, *debugstr, *sampstr, *perstr, *freqstr, *astr, *ostr, *dstr, *typestr ;
tomwalters@0: static char *phasestr ;
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:     {   "period"    ,   "8ms"       ,  &perstr      ,   "period of waveform"                , VAL     },
tomwalters@0:     {   "frequency" ,   "125Hz"     ,  &freqstr     ,   "frequency of waveform"             , VAL     },
tomwalters@0:     {   "phase"     ,   "0"         ,  &phasestr    ,   "phase offset"                      , VAL     },
tomwalters@0:     {   "amplitude" ,   "512"       ,  &astr        ,   "amplitude of waveform"             , VAL     },
tomwalters@0:     {   "mean"      ,   "0"         ,  &ostr        ,   "mean value of waveform"            , 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: float   offset     ;
tomwalters@0: int     type       ;    /* datatype index */
tomwalters@0: 
tomwalters@0: main(argc, argv)
tomwalters@0: int   argc ;
tomwalters@0: char *argv[] ;
tomwalters@0: {
tomwalters@0:     float  T=0, Tr, r, y ;
tomwalters@0:     int    i, n ;
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:     offset     = atof( ostr ) ;
tomwalters@0: 
tomwalters@0:     if ( ( type = typeindex( typestr ) ) < 0 ) {
tomwalters@0: 	fprintf( stderr, "tone: bad type [%s]\n", typestr ) ;
tomwalters@0: 	exit( 1 ) ;
tomwalters@0:     }
tomwalters@0: 
tomwalters@0:     n  = to_p( dstr, samplerate ) ;
tomwalters@0: 
tomwalters@0:     if ( isstr( perstr, optdflt( option, "period" ) ) )
tomwalters@0: 	T = 1.0 / to_Hz( freqstr, samplerate ) ;
tomwalters@0:     else
tomwalters@0: 	T = to_s( perstr, samplerate ) ;
tomwalters@0: 
tomwalters@0:     Tr = TWOPI / ( samplerate * T ) ;   /* period of max resolution */
tomwalters@0: 
tomwalters@0:     if ( iststr( phasestr, "sine" ) )   /* start */
tomwalters@0: 	r = 0 ;
tomwalters@0:     else if ( iststr( phasestr, "cosine" ) )
tomwalters@0: 	r = TWOPI / 4 ;
tomwalters@0:     else if ( iststr( phasestr, "antisine" ) )
tomwalters@0: 	r = TWOPI / 2 ;
tomwalters@0:     else if ( iststr( phasestr, "anticosine" ) )
tomwalters@0: 	r = 3 * TWOPI / 4 ;
tomwalters@0:     else if ( isstr( phasestr + strlen( phasestr ) - 3, "deg" ) )
tomwalters@0: 	r = TWOPI * ( atof( phasestr ) / 360. ) ;
tomwalters@0:     else
tomwalters@0: 	r = TWOPI * ( to_s( phasestr, samplerate ) / T ) ;
tomwalters@0: 
tomwalters@0:     for ( i = 0  ; i < n ; i++, r += Tr ) {
tomwalters@0: 	y = amplitude * sin(r) + offset ;
tomwalters@0: 	writeitem( &y, type, 1, stdout ) ;
tomwalters@0:     }
tomwalters@0: }