CTITLESASINC  -- GENERATE FREQUENCY DOMAIN INTREPOLATION COEFFICIENTS
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     MM-DD-YY
C     REVISED     02-20-89 JJC  FOR SPARC PRODUCTION.
CA
CA  THIS SUBROUTINE SETS UP FREQUENCY DOMAIN INTERPOLATION COEFFICIENTS
CA  BASED ON A WINDOWED SINC FUNCTION.  THE COEFFICIENTS ARE BASED ON
CA  AN LR   LENGTH WINDOW.
CA  THE COEFFICIENTS ARE COMPUTED FOR EVERY 1/100 OF A SAMPLE INCREMENT
CA  AND STORED IN COEF.  THE COMPLEX NORMALIZATION FACTOR FOR EACH
CA  COEFFICIENT IS STORED IN CNORM.
CA
CA    SUBROUTINE SASINC(LR,COEF,CNORM,CSHIFT,IPR)
CA
CA   LR    -  INPUT - INTERPOLATION FILTER LENGTH
CA   COEF  - OUTPUT - INTERPOLATION FILTER COEFFICIENTS
CA   CNORM - OUTPUT - INTERPOLATION FILTER NORMALICATION
CA   CSHIFT- OUTPUT - TIME SHIFT FACTOR FOR DEMODULATION/MODULATION
CA   IPR   -  INPUT - SPARC LOGICAL PRINT UNIT
CA
      SUBROUTINE SASINC(LR,COEF,CNORM,CSHIFT,IPR)
C
      COMMON/CMPFKC/IF1,LNT,LW,LW2,IW1,ALPHA,SCALE,CMIN,VMUTE,AFFR,IKHHI
      COMPLEX CNORM(101),CC,CSHIFT(*)
      DIMENSION COEF(LR,101)
      DIMENSION AA(14),RW(12),FF(13),GG(12)
      DATA PI/3.1415926536/
      DATA A,B/0.54,0.46/
C
      CALL ARSET(COEF, LR*101, 0.0)
      CALL ARSET(CNORM, 2*101, 0.0)
      LRD2 = LR/2
C
      COEF(LRD2,1)     = 1.0
      CNORM(1) = 1.0
C
C  TRIANGLE WINDOW + SINC
C
C     DO 50 I=2,100
C     DN = (I-1)/100.
C     PIDN = PI*DN
C     C = COS(PIDN)
C     S = SIN(PIDN)
C     CC = CMPLX(C,+S)
C     CNORM(I) = CC
CC    RC = (S/(LRD2+1)/PI)
C     RC = (S/LRD2/PI)
C     DO 40 J=1,LR
C     RM=J-LRD2
C     DD = DN-RM
CC    COEF(J,I) = RC*((LRD2+1-ABS(DD))/DD)
C     COEF(J,I) = RC*((LRD2-ABS(DD))/DD)
C  40 CONTINUE
C  50 CONTINUE
C
C
C  HAMMING WINDOW + BAND LIMITED SINC
C
C     DO 50 I=2,100
C     DN = (I-1)/100.
C     PIDN = PI*DN*AFFR
C     C = COS(PIDN)
C     S = SIN(PIDN)
C     CC = CMPLX(C,+S)
C     CNORM(I) = CC
C     RC = 1.0/(PI*AFFR)
C     DO 40 J=1,LR
C     RM=J-LRD2
C     DD = DN-RM
C     COEF(J,I) = RC*(A+B*COS(PI*DD/LR))*SIN(AFFR*PI*DD)/DD
C  40 CONTINUE
C  50 CONTINUE
C
C
C  OPTIMAL FILTER COEFFICIENTS FROM MCOFGN
C
      DO 50 I=2,100
      DN = (I-1)/100.
      PIDN = PI*DN*AFFR
      C = COS(PIDN)
      S = SIN(PIDN)
      CC = CMPLX(C,+S)
      CNORM(I) = CC
   50 CONTINUE
           BW = AFFR
           CALL MCOFGN(LR,BW,RW,GG,FF,AA,COEF(1,2))
C
      COEF(LRD2+1,101) = 1.0
      CNORM(101) = CNORM(51)**2
C
C DEMODULATION FACTORS
C
      DO 60 IW=1,LW
      N=IW-1
      ARG = PI*AFFR*N
   60 CSHIFT(IW) = CMPLX(COS(ARG),SIN(ARG))
      CSHIFT(LW+1) = 0.0
      CSHIFT(LW+2) = 0.0
      CSHIFT(LW+3) = 0.0
      CSHIFT(LW+4) = 0.0
C
C     WRITE (IPR,8112) AFFR
C8112 FORMAT('   AFFR =',F8.4,/)
C     DO 100 I=1,101
C     WRITE (IPR,8111) I,CNORM(I),(COEF(J,I),J=1,LR)
C8111 FORMAT('   COEF =',I5,2F8.4,5X,12F6.3)
C 100 CONTINUE
C
      RETURN
      END