Agilent Technologies E5071C Manual page 1136

When you use one of the objects listed above, the base index
•
number of the array is always 0 even if the declaration section
contains the "Option Base 1" statement, which specifies the use
of the base array index of 1.
For example, you may wish to read the formatted data array for a
particular trace in its entirety (including all measurement points), display
the data in the echo window, and then write the data into another trace.
How to implement such a process can be better understood with the aid of
a sample program.
Programming
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