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


    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 or Channel).

      - 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 upper and lower side
        bands. A single frequency-dependent polynomial is fitted, a high de-
        gree might be necessary for the phase, if band edges are used (up to
        20 is feasible).

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

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

Gildas manager 2019-02-20