SOLVE RF_PASSBAND

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SOLVE RF_PASSBAND

            CLIC\SOLVE RF_PASSBAND [da] [dp] [/PLOT] [/SPECTRUM] [/RESET]
            CLIC\SOLVE RF_PASSBAND [/IGNORE a1 a2 ...] [/CROSSED]

        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 (Frequen-
        cy, Channel -- deprecated, or Spectrum). A baseband should have been se-
        lected beforehand (see SET BBAND).

          -  For  frequency-dependent  RF  passabnd calibration (SET RF_PASSBAND
            FREQUENCY, recommended): the resolution is normally done  using  all
            the  spectral subbands plotted together, as a function of intermedi-
            ate frequency. It should be done separately for  each  baseband  and
            sideband (if applicable). A single frequency-dependent polynomial is
            fitted, a high degree might be necessary  for  the  phase,  if  band
            edges are used (up to 50 is feasible).

          - 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 frequen-
            cy-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_PASS-
        BAND FREQUENCY|CHANNEL to apply one or the other.

        Option /SPECTRUM supersedes any polynomial given and does use  the  data
        points  plotted  to  derive  a  bandpass solution. It will factorize the
        gains per antenna if SET RF ANTENNA is selected. The  bandpass  solution
        will then be computed by linear interpolation of these data points.

        Option  /PLOT will plot the polynomial fits over the data. Option /RESET
        will reset polynoms in memory.

        Option /IGNORE works only in ANTENNA mode. Antennas selected  after  op-
        tion  will be ignored in the factorization. This is useful for basebands
        of the narrow-correlator when more  than  6  antennas  were  used  (with
        WIDEX).

        Option  /CROSSED allows to store the RF solution in another memory slot,
        which is used in the case of  STORE  RF  /POLARISATION  (see  associated
        HELP).