CTITLESAMPFKE  -- PERFORM COSINE-BELL TAPER ON TRANSFORMED TRACES
C***********************************************************************
C                 COPYRIGHT ATLANTIC RICHFIELD COMPANY 1991            *
C***********************************************************************
CA    AUTHOR      JAMES SUN/BRUCE VERWEST
CA    DESIGNER    JAMES SUN/BRUCE VERWEST
CA    LANGUAGE    VS FORTRAN
CA    SYSTEM      IBM / CRAY
CA    WRITTEN     07/01/87
C     REVISED     12-04-87  BJV  INCREASED BUFFER BLOCKING ARRAY        00070009
C                                DIMENSIONS TO 39 AND 19.               00080009
C     REVISED     02-20-89  JJC  FOR SPARC PRODUCTION.
CA
CA    SUBROUTINE SAMPFKE(NHIN,P)
CA
CA    THIS SUBROUTINE PERFORMS A COSINE-BELL TAPER ON THE TEMPORAL
CA    FOURIER TRANSFORMED OFFSET TRACES WITHIN A DEPTH POINT. THE
CA    WEIGHTING OF THE OFFSET TRACES DEPENDS ON THE NUMBER OF OFFSET
CA    TRACE IN THE DEPTH POINT. THIS TAPERING IN PERFORMED PRIOR TO
CA    THE SPATIAL FOURIER TRANSFORM OVER OFFSET COORDINATE XH.
CA
CA**********************************************************************
CA    ARGUMENTS:
CA
CA    NHIN         INPUT          THE NUMBER OF OFFSET TRACES WITHIN
CA                                THE CURRENT DEPTH POINT
CA
CA    P            INPUT/         COMPLEX ARRAY WHICH CONTAINS THE
CA                 OUTPUT         TEMPORAL FOURIER TRANSFORMED OFFSET
CA                                TRACES WITHIN A DEPTH POINT UPON INPUT
CA                                AND THE SPATIAL COSINE-BELL TAPERED
CA                                RESULT UPON EXIT
CA
CA**********************************************************************
C
      SUBROUTINE SAMPFKE(NHIN,P)
C
      COMMON/CMPFKC/IF1,LNT,LW,LW2,IW1,ALPHA,SCALE,CMIN,VMUTE,AFFR,IKHHI
      COMMON/CMPFKT/NT,DT,NW,DW,NWD2,NWD21,NWP2
      COMMON/CMPFKH/NH,DH,NKH,DKH,NKHD2,NKHD21,NKH2,IHBEG
      COMMON/CMPFKB/IKXBF(39),IWBF(19),MKXBF(39),MWBF(19),
     +              NBF,MBF,NKXBF,NWBF
C
      COMPLEX P(LNT/2,1)
C
      PI=3.14159265
      IF (NHIN .EQ. 1) THEN
          MH = 2
          IH1 = NHIN
      ELSE
          MH=NHIN/10
          MH=MAX0(MH,3)
          IH1=NHIN-MH+2
      ENDIF
      AMH=1./FLOAT(MH)
C
C APPLY FAR TAPER
C
      AH=1.
      DO 100 IH=IH1,NHIN
      AH=AH-AMH
      WGHT=.5*(1.-COS(AH*PI))
  100 CALL CSSCAL(LW,WGHT,P(1,IH),1)
C
      RETURN
      END