pnutil.c

来自「产生PN序列」· C语言 代码 · 共 36 行

/*
 * $Log: pnutil.c,v $
 * Revision 1.1  2000/05/03 14:30:04  bjc97r
 * Initial revision
 *
 */
char *_pnutil_id = "$Id: pnutil.c,v 1.1 2000/05/03 14:30:04 bjc97r Exp $";

int pn_xcorr( char *pn1, char *pn2, int offset, int size )
  /* It finds the cross-correlation of the two given sequence in pn[].
     size is the array size of pn?[].
     The calculated cross-correlation before scaling is returned. */
{
  int val;  /* calculated auto-correlation value */
  int i, j; /* loop indices */
  
  val = 0;
  for( i = 0, j = offset; i < size; i++, j++ ) {
    if ( j >= size ) j -= size;
    if ( pn1[i] == pn2[j] )
      val++;
    else
      val--;
  }
  
  return val;
}

int pn_acorr( char *pn, int offset, int size )
  /* It finds the auto-correlation of the given sequence in pn[].
     size is the array size of pn[].
     The calculated auto-correlation before scaling is returned. */
{
  return pn_xcorr( pn, pn, offset, size );
}