; INTERPOL
;---------------------------------------------------------------
;! specifies the type of averaging done on the complex gains
;# ADVERB CALIBRATION
;-----------------------------------------------------------------------
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;-----------------------------------------------------------------------
INTERPOL  LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
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INTERPOL
Type: Adverb  (String*4)
Use:  Standard data selection adverb; used to specify the
      interpolation function to be applied to the gain table:
      In CLCAL:
         '    ' = linear vector interpolation with no SN smoothing.
         '2PT ' = linear vector interpolation with no SN smoothing.
         'SELF' = Use only SN solution from same source which is
                  closest in time.
         'POLY' = Fit a polynomial to the SN rates and delays.  Use
                  the integral of the rate polynomial for the phases.
         'SIMP' = Simple linear phase connection between SN phase
                  entries, assumes phase difference less than 180 deg.
         'AMBG' = Linear phase connection using rates to resolve phase
                  ambiguities.
         'CUBE' = As AMBG but fit third order polynomial to phases and
                  rates.
         'MWF ' = Median window filter of SN table before 2PT
                  interpolation
         'BOX ' = Boxcar smoothing of SN table before 2PT
                  interpolation, boxcar width set by adverb INTPARM.

      In CLSMO and SNSMO, values are
         'BOX ' = boxcar smoothing.
         'MWF ' = Median window filter
         other => boxcar
      This adverb is only relevant when the data being operated
      on has an associated gain table.
Null value:  '    ' see above.
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