diff tools/cosine.c @ 0:5242703e91d3 tip

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

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/cosine.c	Fri May 20 15:19:45 2011 +0100
@@ -0,0 +1,102 @@
+/*
+    cosine.c    generate a cosine window
+    --------
+
+    1. Hann (or raised cosine) window
+
+	w[n] = 0.5 [ 1 - cos( TWOPI . n/(N-1) ) ]
+
+    2. Hamming window
+
+	w[n] = 0.54 - 0.46 cos( TWOPI . n/(N-1) )
+
+    Both windows are defined for 0 <= n <= N-1 and are zero otherwise.
+
+
+*/
+
+#include <stdio.h>
+#include <math.h>
+#include "options.h"
+#include "units.h"
+#include "strmatch.h"
+#include "sigproc.h"
+
+
+char applic[]     = "generate a cosine window." ;
+
+static char *helpstr,  *debugstr, *sampstr,  *hammstr ;
+static char *scalestr, *typestr,  *sizestr ;
+
+static Options option[] = {
+    {   "help"      ,   "off"       ,  &helpstr     ,   "help"                                      , DEBUG   },
+    {   "debug"     ,   "off"       ,  &debugstr    ,   "debugging switch"                          , DEBUG   },
+    {   "samplerate",   "20kHz"     ,  &sampstr     ,   "samplerate "                               , VAL     },
+    {   "size"      ,   "10ms"      ,  &sizestr     ,   "Size of window"                            , VAL     },
+    {   "Hamming"   ,   "off"       ,  &hammstr     ,   "Hamming window (default raised cosine)"    , SETFLAG },
+    {   "scale"     ,   "1000"      ,  &scalestr    ,   "Scale factor for output"                   , VAL     },
+    {   "type"      ,   "short"     ,  &typestr     ,   "Output datatype (short/float)"             , VAL     },
+   ( char * ) 0 } ;
+
+
+int     samplerate  ;
+
+float  *window ;
+int     n      ;
+
+short  *buf    ;
+
+
+main (argc, argv)
+int     argc;
+char  **argv;
+{
+    float f ;
+
+    getopts( option,argc,argv ) ;
+    if ( !isoff( helpstr ) )
+	helpopts( helpstr, argv[0], applic, option ) ;
+
+    samplerate = to_Hz( sampstr ) ;
+    n          = to_p( sizestr, samplerate ) ;
+
+    if ( ison( hammstr ) )
+	window = hamming( n ) ;
+
+    else if ( isoff( hammstr ) )
+	window = raised_cosine( n ) ;
+
+    else {
+	fprintf(stderr,"cosine: unknown window [%s]\n", hammstr) ;
+	exit( 1 ) ;
+    }
+
+    if ( iststr( typestr, "float" ) ) {
+	scalar( window, n, atof( scalestr ) ) ;
+	fwrite( window, sizeof(float), n, stdout ) ;
+    }
+
+    else if ( iststr( typestr, "short" ) ) {
+	buf = (short *)malloc( n * sizeof(short) ) ;
+	if ( ( f = ftos( window, buf, n, atof( scalestr ) ) ) < 1. )
+	    fprintf( stderr,"Warning: 16-bit overflow. Try scale factor < %f\n", f ) ;
+	fwrite( buf, sizeof(short), n, stdout ) ;
+    }
+
+    else
+	fprintf(stderr,"cosine: unknown datatype [%s]\n", typestr) ;
+}
+
+
+scalar( y, n, scale )
+float  *y ;
+int     n ;
+float   scale ;
+{
+    int  i ;
+
+    if ( scale != 1. ) {
+	for ( i=0 ; i < n ; i++ )
+	    y[i] *= scale ;
+    }
+}