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).