SPECIFY FREQUENCY

        SPECIFY [*|Buffer|FileName.Type] FREQUENCY Arg [Keyword Value ...]
    Modify the rest frequency(ies) and recompute the velocity scale  accordingly
    for all buffers, or the specified SIC variable or Gildas file.

    If  Arg  is a number or scalar variable, it should contain the new rest fre-
    quency in MHz. In this mode, there may be other arguments  to  specify  e.g.
    the VELOCITY or LINENAME at the same time.

    If it is the name of a SIC array variable, variable Arg must be a 1-D double
    precision array that contains frequencies  (in MHz) for every channel of the
    UV  data  to which it applies. This is by default the current UV data if not
    specified. This mode allows to handle irregular frequency sampling that  oc-
    curs e.g. in JVLA data sets. No further argument is allowed in this mode.