lgold.c

产生PN序列

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

#include <stdio.h>
#include <stdlib.h>

#include "lgold.h"
#include "lmseq.h"

/*
 * It creates a long Gold code generator with the two preferred m-sequences
 * with the given seeds. The Gold code generator is returned.
 */
LGold * lgold_create( unsigned deg, char *p0, char *p1, u2long s0, u2long s1 )
{
  LGold *gold;

  if ( deg > 63 ) {
    fprintf(stderr, "lgold_create: ..cannot handle deg > 63\n");
    return NULL; 
  }

  gold = (LGold*) malloc ( sizeof(LGold) );
  gold->mseq0 = lmseq_create( deg, p0, s0.h, s0.l );
  gold->mseq1 = lmseq_create( deg, p1, s1.h, s1.l );

  return gold;
}

/* lgold_free() deallocates the memory space for the Gold sequence generator.*/
void lgold_free( LGold *gold )
{
  lmseq_free( gold->mseq0 );
  lmseq_free( gold->mseq1 );
  free( gold );
}

/* lgold() gives the next Gold sequence. The sequence is unipolar, ie 1 or 0.*/
char lgold( LGold *gold )
{
  return lmseq(gold->mseq0) ^ lmseq(gold->mseq1);
}