User`s manual

AFG Memory Description
The segment memory that stores the segment list as DAC codes can store
the codes either in the Signed or Unsigned number format. This memory
uses 16-bit integer values for the codes. To change the number format to a
different format, the memory must be completely empty before selecting the
different format.
Because of hardware restrictions, the segment space in memory allocates
for a multiple of 8 words for each waveform segment.
452 Block Diagram Description Chapter 10