_____________________________________________________________________ BT BACKWARD TRANSFORM Use REAL and COMPLEX files as storage registers to contain your results ie. OPTION MAP REAL COMP BT 3 S*T S(x)*T(x) ______________________________________________________________________ TYPE OPTIE 22-OCT-1981 04:23:50.06 >>>.BT OPTION .BT NPTS=512 OPEN INPUT FILE WITH COMPLEX DATA FILIC=COFT ! See CR.DOC where this was created. There are 3 maps in the file Reading from the file 76 rows of 512 pixels in C8 format MAPIC=2 ROWI=1:76 MAPOC=3 OPEN OUTPUT FILE FOR REAL TRANSFORM FILOR=REFT There are 3 maps in the file Reading from the file 76 rows of 512 pixels in R4 format MAPOR=3 _____________________________________________________________________