/*****************************************************************************//*   FIle Name : detect_drift.c                                              *//*   Description : Wi-Max detection of Drift                                 *//*   author : miffie                                                         *//*   Date   : oct/18/05                                                      *//*   Copyright (c) 2005 miffie   All rights reserved.                        *//*****************************************************************************////////////////////////////////////////////////////////////////////////////////double detect_drift( struct complexset datain , short distance, double coef,                      char offset ) { // double  lpfout , lpfreg, drift ;struct	complex tmp1 , tmp2 ;int	ii  ;int     size ;//double  drift_phase, drift_amount ; //Main   lpfout = 0 ;  size = datain.size-distance ;    //search  for(ii=offset;ii<size;ii++) { //each symbol      tmp1.realp  = datain.data[ii+distance].realp ;      tmp1.image  = datain.data[ii+distance].image ;      tmp1 = cordic ( tmp1 ) ;      tmp2.realp  = datain.data[ii].realp ;      tmp2.image  = datain.data[ii].image ;      tmp2 = cordic ( tmp2 ) ;      //-pi<=tmp1<pi      //-pi<=tmp2<pi      drift = tmp1.image-tmp2.image ;      //-2pi<drift<2pi => -pi<drift<pi Normalization      drift = (drift>pi)  ? drift -2*pi :              (drift<-pi) ? drift +2*pi : drift ;      //if phase is different from previous one, correct      drift = ((drift>=(pi/4.0))&(drift<(3.0*pi/4.0))) ? drift - (pi/2.0) :                (drift>=(3.0*pi/4.0)) ? drift - pi :               (drift<=(-3.0*pi/4.0)) ? drift + pi :              ((drift<=(-pi/4.0))&(drift>(-3.0*pi/4.0))) ? drift + (pi/2.0) : drift ;      //lpfout += drift ;        lpfout = iir_lpf( drift, lpfout, coef )   ;  } //each symbol  lpfout = lpfout/distance ;  PRINTF("detect_drift size=%d %8.5f\n", datain.size , lpfout) ;  return( lpfout ) ;} //detect_drift