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        CLIC\TABLE Name [OLD|NEW] [/COMPRESS tmax uvmax]
        [/RESAMPLE nc ref val inc code shape width]  [/FFT]
        [/FREQUENCY name rest-freq] [/DROP  n1 n2]

    This  command  will  create an UV data Table from the current index.  is
    not given, the most recently created table will be extended.  Next argu-
    ment  may be OLD (default value if not specified) to extend and existing
    table, or NEW to create a new table.

    The bands and subbands used must have been given by the command SET  SE-
    LECTION. The weighting mode can be modified by the command SET WEIGHTS.

    TABLE /RESAMPLE nc ref val inc code [shape width /FFT]

        Option  /RESAMPLE  enables  to  resample data on a new spectral grid
        (for line data).  'nc' is the output number of channels,  'ref'  the
        reference  channel,  'val' the value of velocity or frequency offset
        (with respect to the rest frequency) at the reference channel, 'inc'
        the  resolution, 'code' is "V" if the value 'val' and the resolution
        'inc' are in velocity units, "F" for frequency units.

        The reference channel thus corresponds to the given 'val'  velocity,
        or to the offset 'val' in MHz from the rest frequency present in the
        header or modified by option /FREQUENCY.

        Resampling is done by default through linear interpolation of  input
        channel  data.  Resampling  may  also be done (using option /FFT) in
        Fourier space by cut-off or extrapolation (by zeroes) of the Fourier
        components,  after deconvolution by the channel response of the cor-
        relator (due to on-line apodization), and followed by  reconvolution
        to  produce frequency channels of the given 'shape' and 'width'. Al-
        lowed shapes are:
          TBox = a box in delay space (unapodized correlator)
          Ppar = a parabola in delay space (apodized  correlator)  (the  de-
          FBox = a box in frequency space (square filter)
          FTri = a triangle in frequency space (Hanning smoothed square fil-
        The width is the channel width in units of channel  separation  (de-
        fault 1).

        Option  /FFT  is  not recommended when joining together several sub-
        bands to produce a single spectrum, with a limited number  of  broad
        channels.   In  those  cases  using the FFT could produce a spectrum
        with "holes" at the points between subbands with limited overlap.

    TABLE /FREQUENCY  name rest-freq

        Option /FREQUENCY is used to redefine the rest  frequency  (in  MHz)
        and  line name for the output table.  The velocity scale is computed
        accordingly.  This rest frequency will correspond to  the  reference
        channel in option RESAMPLE.


        When  processing each scan, CLIC checks whether a number of position
        parameters are consistent with those defined in  the  table  header.
        Option  /NOCHECK  allows to switch off this checking.  Arguments can
        be given to switch off only part of  the  parameters  (SOURCE  name,
        POINTING direction, PHASE center, EPOCH of coordinates). This option
        is intended for building tables with inconsistent parameters  (typi-
        cal  exemple  is a different source name...). It is potentially dan-
        gerous and is to be used with caution.


        Option /DROP enables to drop the first 'n1' and last 'n2'   channels
        in each subband of the OLD spectral correlator. For the NEW spectral
        correlator (data taken since summer 1992), it  is  replaced  by  the
        commands SET GIBBS and SET DROP.

    TABLE /COMPRESS tmax uvmax

        Option  /COMPRESS is used to compress the data  before  writing  the
        table.   This  works like the COMPRESS command, but no  intermediate
        file is written. Very seldom used.


Gildas manager 2022-01-17