SUBROUTINE TSHIFT(M,OATA,A,DELF ) 

 C*****THIS SUBROUTINE CONTAINS 26 STATEMENTS. 



C*****TSHIFT APPLIES EFFECTS OF TIME SHIFT ON REAL AND IMAGINARY PARTS OF THE 

 C*****FOURIER TRANSFORM. 



C*****M -= POWER OF 2 WHICH IS EQUAL TO THE NUMBER OF REAL OR IMAGINARY PARTS 

 C***** OF THE FOURIER TRANSFORM. 



C*****DATA -= SERIES ... REAL PARTS ARE ODD INDEX, IMAGINARY PARTS ARE EVEN. 

 C*****A -= YAXIS SHIFT, IE. TO CORRECT THE FOURIER TRANSFORM OF A FUNCTION 

 WHICH 



C***** HAS BEEN SHIFTED A DATA INTERVALS IN THE +X DIRECTION, SIGN OF A IS 

 +, 

 C*****OELF -= NORMALIZED FREQUENCY INCREMENT. 



DIMENSION DATA(l) 



M2=2*2**M 



PI=3. 1415926536 



SFT=2.0*PI*A*DELF 



DO 1 I=1,M2,2 



J=I+1 



TRE=DATA(I) 



TIM=DATA(J) 



K=I/2 



ARG=SFT*K 



CN=COS(ARG) 



SN=SIN(ARG) 



DATA(I)=TRE*CN-TIM*SN 

 1 DATA(J)=TIM*CN+TRE*SN 



RETURN 



END 



201 



