next up previous contents index
Next: SOLVE SKYDIP Up: SOLVE Previous: SOLVE POINTING   Contents   Index


SOLVE RF_PASSBAND

      CLIC\SOLVE RF_PASSBAND [da] [dp] [/PLOT]

  *** THIS HELP HAS NOT BEEN UPDATED FOR THE NGRX ***

  Solve for passband calibration curves, by fitting it to the amplitudes and
  phases.  The  current  index  should  contain  calibration observations of
  strong continuum sources (RF passband calibrator). The behaviour  of  this
  command  depends on the current mode of RF passband calibration (Frequency
  or Channel).

    - For frequency-dependent RF passabnd calibration (SET RF_PASSBAND  FRE-
      QUENCY,  recommended):  the  resolution is normally done using all the
      spectral subbands plotted together, as a function of intermediate fre-
      quency. It should be done separately for upper and lower side bands. A
      single frequency-dependent polynomial is fitted, a high  degree  might
      be necessary for the phase, if band edges are used (up to 20 is feasi-
      ble).

    - For channel dependent RF passband calibration (SET  RF_PASSBAND  CHAN-
      NEL)

      (i)  For  continuum, the data itself is directly stored as calibration
      values (this gives a channel-dependent passband curve).  In addition a
      polynomial  is  fitted and optionally plotted (this gives a frequency-
      dependent passband curve).

      (ii) For spectral subbands, polynomials are  fitted   and   optionally
      plotted, as a channel-dependent passband curve.

  The  degrees  for  polynomials are 'da' for amplitude, 'dp' for phase (de-
  faults 0 and 1). Command STORE should be used next  to  store  the  fitted
  function  in the header of source observations. Both channel dependent and
  frequency dependent curves can be stored; Use command SET RF_PASSBAND FRE-
  QUENCY|CHANNEL to apply one or the other.

  Option /PLOT will plot the polynomial fits over the data.


Gildas manager 2011-04-01