AIPS HELP file for ICHANSEL in 31DEC09

As of Sat Nov 21 23:57:58 2009

HELP SECTION

ICHANSEL
Type: Adverb  (REAL, 4 elements x 20 rows)
Use:  Data selection adverb used to specify a list of start and stop
      channel numbers plus an increment AND IF NUMBER to be used in
      some way, such as to be averaged to form a pseudo-continuum
      channel.  Up to 20 sets of channel numbers/IFs can be specified.
      The first two elements specify the start and stop channel
      numbers, the third specifies the increment within that range,
      i.e.if CHANSEL = 10,20,2 that means take every other channel in
      the range 10 - 20, so that channels 10,12,14,16,18,20 would be
      averaged together.  The fourth element specifies the IF to which
      the previous three apply.
Null Value:  0
      A completely null value means use all channels in some tasks:
         ICHANSEL(1,i) <= 0  =>  1
         ICHANSEL(2,1) <= 0  =>  Nchan
         ICHANSEL(2,i) <= 0  =>  (i > 1) -> no more channel sets
         ICHANSEL(3,i) <= 0  =>  1
         ICHANSEL(4,i) <= 0  =>  all IFs
      BPASS, CPASS, AVSPC use the center 75 percent of the channels for any
      IF for which no ICHANSEL was specified.

EXPLAIN SECTION