comparison tools/ptrain.c @ 0:5242703e91d3 tip

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

+/*
+  ptrain.c    generate a pulse train of binary shorts.
+  --------
+    Generate samples of a pulse train at a given sample rate.
+    Specify pulse amplitude and width (in s, ms, or p (sample points) ),
+    and also the period of the waveform (in s, ms, or p (sample points) ).
+    The pulse amplitude is the pulse height above the zero level, which is
+    set by the offset option. The offset is "0" by default so that pulses
+    of any given amplitude are non-negative by default.
+
+    Output samples in binary shorts for the given waveform duration.
+
+    Non-fixed period pulse trains:
+    If a filename is given, then the period of the output pulse train is
+    taken from the file. Binary shorts read from the file are subsequent
+    periods in samples. Periods are output until the file is empty.
+
+
+Examples:
+
+1. A pulse train with period 100 samples and pulse width 1 sample:
+
+ptrain period=100p width=1p
+
+2. A pulse train with period 8ms at 20KHz and pulse width 4 samples
+
+ptrain -p8ms -s20000 -w4
+
+3. A square wave (pulse width = half period) of period 4ms, sampled at 10kHz
+
+ptrain period=4ms width=2ms samplerate=10kHz
+
+3. A square wave of period 4ms with zero mean value
+
+ptrain period=4ms width=2ms offset=0
+
+*/
+
+
+#include <stdio.h>
+#include <math.h>
+#include "options.h"
+#include "units.h"
+#include "strmatch.h"
+
+char applic[]  = "generate a pulse train of binary shorts. " ;
+char usage[]   = "ptrain [options]" ;
+
+static char *helpstr, *debugstr, *sampstr, *pstr, *astr, *ostr, *wstr, *dstr, *phstr ;
+
+static Options option[] = {
+    {   "help"      ,   "off"       ,  &helpstr     ,   "help"                     , DEBUG   },
+    {   "debug"     ,   "off"       ,  &debugstr    ,   "debugging switch"         , DEBUG   },
+    {   "samplerate",   "20kHz"     ,  &sampstr     ,   "samplerate "              , VAL     },
+    {   "duration"  ,   "500ms"     ,  &dstr        ,   "duration of waveform"     , VAL     },
+    {   "period"    ,   "8ms"       ,  &pstr        ,   "period of pulse train"    , VAL     },
+    {   "amplitude" ,   "1024"      ,  &astr        ,   "pulse amplitude"          , VAL     },
+    {   "width"     ,   "4p"        ,  &wstr        ,   "pulse width"              , VAL     },
+    {   "offset"    ,   "0"         ,  &ostr        ,   "dc offset"                , VAL     },
+    {   "phase"     ,   "0"         ,  &phstr       ,   "phase offset"             , VAL     },
+   ( char * ) 0 } ;
+
+
+main(argc, argv)
+int   argc ;
+char *argv[] ;
+{
+    FILE   *fp, *fopen() ;
+    short  a, z = 0;   /* Zero */
+    int    i, j, samplerate ;
+    int    T, w, n, phase ;
+
+    i = getopts( option,argc,argv ) ;
+    if ( !isoff( helpstr ) )
+	helpopts3( helpstr, argv[0], applic, usage, option ) ;
+
+    samplerate = to_Hz( sampstr ) ;
+    T = (int)to_p( pstr, samplerate ) ; /* period */
+    w = (int)to_p( wstr, samplerate ) ; /* width */
+    n = to_p( dstr, samplerate ) ;      /* duration in points */
+
+    z = atoi( ostr ) ;      /* zero level set to the dc offset (default 0) */
+    a = atoi( astr ) + z ;  /* amplitude (pulse height above zero level)   */
+
+
+    if ( ( phase = (int)to_p( pstr, samplerate ) ) > 0 ) {   /* initial phase offset */
+	for (j=0 ; j<phase ; j++ )
+	    fwrite(&z, sizeof(short), 1, stdout);
+    }
+
+    /* Using given arg T to generate fixed periods */
+
+    if ( i == 0 ) {
+	for (i=0 ; i<n ;  ) {
+	    for (j=0 ; j<w && i<n ; j++, i++)
+		fwrite(&a, sizeof(short), 1, stdout);
+	    for ( ; j<T && i<n ; j++, i++)
+		fwrite(&z, sizeof(short), 1, stdout);
+	}
+    }
+
+
+    /* Reading periods T from file argv[argc-i] */
+
+    else {
+	if ( ( fp = fopen( argv[argc-i], "r" ) ) == NULL ) {
+	    fprintf(stderr,"can't open %s\n", argv[argc-i] );
+	    exit(1);
+	}
+	while ( fread( &T, sizeof(short), 1, fp ) ) {
+	    for (j=0 ; j<w ; j++)
+		fwrite(&a, sizeof(short), 1, stdout);
+	    for ( ; j<T ; j++)
+		fwrite(&z, sizeof(short), 1, stdout);
+	}
+	fclose( fp ) ;
+    }
+
+}