AIPS NRAO AIPS HELP file for BASRM in 31DEC21



As of Fri Dec 3 2:18:14 2021


BASRM: Task to remove a spectral baseline from total power

INPUTS

INNAME                             Input UV file name (name)
INCLASS                            Input UV file name (class)
INSEQ             0.0     9999.0   Input UV file name (seq. #)
INDISK            0.0        9.0   Input UV file disk unit #
OUTNAME                            Output UV file name (name)
OUTCLASS                           Output UV file name (class)
OUTSEQ           -1.0     9999.0   Output UV file name (seq. #)
OUTDISK           0.0        9.0   Output UV file disk unit #.
SELBAND                            Bandwidth to select (kHz)
SELFREQ                            Frequency to select (MHz)
FREQID                             Freq. ID to select. 0=> all
APARM                              (1) Order of polynomial
                                   (2) > 0 => Write out
                                   polynomials, not spectra
                                   (3) > 0 => print polynomial
                                   coefficients on screen.
ICHANSEL                           Array of start and stop chn
                                   numbers, plus a channel
                                   increment and IF to be used
                                   for channel selection in the
                                   fitting. See HELP ICHANSEL.
                                   Default = center 75 percent of band.

HELP SECTION

BASRM
Task:  This task will copy a uv data set removing a spectral
       baseline from total power data along the way. Cross-power data
       are untouched by this operation. The user is able to fit and
       remove an nth order polynomial from line-free channels of the
       total power spectra.  The fit is done one IF and one polarization
       at a time.

       NOTE: this task does NOT apply flagging or calibration tables
       to the input UV data.  Run SPLIT first if that operation is
       desired.
Adverbs:
  INNAME.....Input UV file name (name).      Standard defaults.
  INCLASS....Input UV file name (class).     Standard defaults.
  INSEQ......Input UV file name (seq. #).    0 => highest.
  INDISK.....Disk drive # of input UV file.  0 => any.
  OUTNAME....Output UV file name (name).     Standard defaults.
  OUTCLASS...Output UV file name (class).    Standard defaults.
  OUTSEQ.....Output UV file name (seq. #).   0 => highest unique
  OUTDISK....Disk drive # of output UV file. 0 => highest w room
  SELBAND....Bandwidth of data to be selected. If more than
             one IF is present SELBAND is the width of the
             first IF required. Units = kHz.
  SELFREQ....Frequency of data to be selected. Units = MHz.
  FREQID.....Frequency identifier to select (you may determine
             which is applicable from the OPTYPE='SCAN' listing
             produced by LISTR). If either SELBAND or SELFREQ
             are set, their values overide that of FREQID.
             However, setting SELBAND and SELFREQ may result in
             an ambiguity.  In that case, the task will request
             that you use FREQID. (.le. 0 => all). If you select
             data with the FREQ adverbs BASRM will renumber the
             FREQID in the output file to 1, i.e. you can set
             FREQID to the default value for all subsequent
             operations on the output file.
  APARM......(1) Order of the polynomial to be removed, 0=>
                 constant offset only.
             (2) if > 0 replace the total power spectra in the
                 output file with the polynomial fitted to the
                 line-free channels rather than just writing
                 out the corrected spectra.
             (3) if > 0 will print fitted polynomial coefficients for
                 each spectrum (IF, polarization, antenna)
  ICHANSEL...Array of start and stop channels plus a channel increment
             and IF, used to select the channels to be fit.  NOTE:
             BASRM forces the channel increment to 1.  For instance, if
             you wished to exclude channels 1 - 10 and 121 - 128 because
             of bandpass effects, and channels 56 - 80 of IF 1 but not IF
             2 because of interference, then you would set ICHANSEL =
             11,55,1,1, 81,121,1,1, 11,121,1,2.  Up to 20 groups of
             start, stop and increment channel numbers plus IF numbers
             can be specified. The default (ICHANSEL = 0) is to use the
             center 75 percent of the band, i.e.
             ICHANSEL(1,1) = (# channels)/8 + 1
                       For example: # channels=16 => ICHANSEL(1,1)=3
             ICHANSEL(2,1) = (# channels + 1)*7/8
                       For example: # channels=16 => ICHANSEL(2,1)=14
             ICHANSEL(3,1) = 1
             ICHANSEL(4,1) = 0 (meaning all IFs).
             If ICHANSEL describes fitting explicitly for some IFs,
             but skips other IFs, then the center 75 percent of the band is
             fit for the skipped IFs.  For example:ICHANSEL=2,6,1,2 =>
             channels 2-6 will be fit for IF=2 and the center 75 percent of the
             band will be fit for the rest of the IFs.

EXPLAIN SECTION



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