Documentation on uvcal

Task: uvcal
Purpose: Apply special processing options to uv-data.
Categories: uv analysis

        UVCAL is a MIRIAD task which applies special processing options
        to uv-data. By default, UVCAL applies the gains file before it
        processes the uv-data into the output file.

Key: vis
        The names of the input uv data sets. Multiple names can be given,
        separated by commas. At least one name must be given.

Key: select
        The normal uv selection commands. See the Users manual for details.
        The default is to process all data. Note that window selection can
        not be used with options=hanning, passband, contsub, or wide.

Key: options
        This gives extra processing options. Several options can be given,
        each separated by commas. They may be abbreivated to the minimum
        needed to avoid ambiguity. Possible options are:
           'nocal'      Do not apply the gains file. By default, UVCAL
                        applies the gains file in copying the data.
           'nopol'      Do not apply the polarization leakage file.
           'nopass'     Do not apply bandpass corrections.
           'nowide'     Do not copy across wide-band channels.
           'nochannel'  Do not copy across spectral channels.
           'contsub'    Continuum subtraction using a linear fit to the real
        		and imaginary parts of each spectral window.
 	                Exclude badchan and endchan specified below.
           'conjugate'  Conjugate visibilities
           'hanning'    Hanning smooth each spectral window.
           'holo'	Replace u,v with dra,ddec for holography.
           'linecal'	Remove phase slope across passband due to line length
        		changes. This option also corrects the phase difference
        		between the wide channels due to line length.
        		options=linecal,wide will re-make the wideband from
        		the channel data after the phase slope is removed.	
        		option can gain in SNR for the wide channels might be
           'passband'   Fit passband to lsb and correct the uv-data.
        	        Can be used when the source is strong. e.g. for
                        planets. The passband is estimated from the lsb,
                        smoothed within each spectral window, and applied
                        to the lsb data. The complex conjugate is applied
        	 	to the usb. This corrects for time variable IF
        		passband errors. The uv-data must contain both
        		sidebands.
           'phasem'	Replace last channel and wideband with predicted
        		line length phase.
           'tpower'	Replace last channel and wideband with predicted
        		phase from tpower difference between antennae pair.
           'unflagged'  Copy only those records where there are some
                        unflagged visibilites.
           'uvrotate'	Rotate uv-coordinates from current to standard epoch.
        		The standard epoch, ra, dec can be changed using PUTHD.
           'wide'	Make wideband from channel average for each sideband 
        		of LO1. Weights by bandwidth and excludes flagged data.
 	                Exclude badchan and endchan specified below.

        NOTE: Options "phasem" and "tpower" cannot be used together.
        	Option "nochannel" cannot be used with "hanning", "passband"
        and "contsub". For these 3 options no processing is performed on the
        wideband data.

Key: badchan
        Number of ranges of bad channels followed by list of up to 20 pairs
        of numbers giving range of channels to exclude from fit in 
        options=contsub and options=wide.  E.g. badchan=3,1,3,15,16,256,257 
        excludes the 3 ranges	(1,3) (15,16) and (265,257)

Key: endchan
        Number of channels to drop from the ends of each spectral
        window in options=passband, and options=contsub. Default=4.

Key: avechan
        Number of channels to average in options=passband. Default=1.

Key: sigma
        Rms noise level used to flag data in options=contsub. All channels
        are flagged if the rms noise level per channel is greater than sigma
        after subtracting the continuum. Endchan and badchan are not included
        in computing the rms. The default is sigma=0. which does not flag
        any data.

Key: scale
        Multiply the data and wideband by cmplx(scale1,scale2). Two values.
        Default is no scaling. If only one value is given it is assumed to
        be a real value. E.g. scale=0,1 multiplies the data by sqrt(-1)

Key: out
        The name of the output uv data set. No default.