      SUBROUTINE PASSF2 (IDO,L1,CC,CH,WA1)
      DIMENSION       CC(IDO,2,L1)           ,CH(IDO,L1,2)           ,
     1                WA1(1)
      IF (IDO .GT. 2) GO TO 102
      DO 101 K=1,L1
         CH(1,K,1) = CC(1,1,K)+CC(1,2,K)
         CH(1,K,2) = CC(1,1,K)-CC(1,2,K)
         CH(2,K,1) = CC(2,1,K)+CC(2,2,K)
         CH(2,K,2) = CC(2,1,K)-CC(2,2,K)
  101 CONTINUE
      RETURN
  102 DO 104 K=1,L1
         DO 103 I=2,IDO,2
            CH(I-1,K,1) = CC(I-1,1,K)+CC(I-1,2,K)
            TR2 = CC(I-1,1,K)-CC(I-1,2,K)
            CH(I,K,1) = CC(I,1,K)+CC(I,2,K)
            TI2 = CC(I,1,K)-CC(I,2,K)
            CH(I,K,2) = WA1(I-1)*TI2-WA1(I)*TR2
            CH(I-1,K,2) = WA1(I-1)*TR2+WA1(I)*TI2
  103    CONTINUE
  104 CONTINUE
      RETURN
      END
