Level 2 Help for DS4

RSEN specifies the sensor which is to be used as a reference sensor.
Allowable values are 1, 2, 3, 4, 5, and 6.  Default is 3.

'AVERAGE specifies that the average of the six sensors is to be
used as the reference.  Default is that averaging is not performed. 

GROUP specifies the number of 6-line sets to be grouped together in
generating the local transfer tables.  Default is 3.  GROUP should be odd.

FILTER is a list of weights to be used in performing a low-pass filter
of the reference CDF.  The weights should be integer, and in number, less 
than 19 and odd.  The default is not to perform filtering.