	SUBROUTINE FWINDW(IWINDW)
C
	COMMON /WINBLK/ WINDOW(1024)
	DATA TWOPI /6.2831853/
C
	GO TO (100,200,300) IWINDW+1
	PRINT*,'REQUESTED WINDOW DOES NOT EXIST'
 100	CONTINUE
	PRINT*,'IWINDW =',IWINDW,'  NO WINDOWING'
	DO N = 1,1024
	  WINDOW(N) = 1.
	ENDDO
	RETURN
 200	CONTINUE
C	PRINT*,'IWINDW =',IWINDW,'  HAMMING'
	ALPHA = .54
	GO TO 310
 300	CONTINUE
	ALPHA = .5
	PRINT*,'IWINDW =',IWINDW,'  HANNING'
 310	CONTINUE
	SUMSQ = 0.
	DO N = 1,1024
	  WINDOW(N) = ALPHA + (ALPHA-1.)*COS(TWOPI*(N-1)/1024.)
	  SUMSQ = SUMSQ + WINDOW(N)**2 
	ENDDO
	RMS = SQRT(SUMSQ/1024.)
	DO N = 1,1024
	  WINDOW(N) = WINDOW(N)/RMS
	ENDDO
	RETURN
	END

