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calibrater.calave - Function

	Package	synthesis
	Module	calibrater
	Tool	calibrater

Average calibration solutions over fields, spectral windows, and/or time

Synopsis
calave(tablein, tableout, fldsin, spwsin, fldsout, spwout, t, append, mode, verbose)

Arguments

tablein	in	Input calibration table name. No default
		Allowed:	String
tableout	in	Output calibration table name. No default
		Allowed:	String
fldsin	in	Input field id(s). No default
		Allowed:	Vector of integers
spwsin	in	Input spectral window id(s). No default
		Allowed:	Vector of integers
fldsout	in	Output field id(s). No default
		Allowed:	Vector of integer
spwout	in	Output spectral window. No default
		Allowed:	Integer
t	in	Averaging time (s). Default is to just copy solutions
		Allowed:	Float
		Default:	-1.0
append	in	Append to existing table?
		Allowed:	Boolean
		Default:	F
mode	in
		Allowed:	String from RI or AP
		Default:	'RI'
verbose	in	Write extra information to logger about proceses
		Allowed:	T or F
		Default:	'T'

Returns
Bool

Description

This function can be used to average calibration solutions over fields, spectral windows, and/or time. It is useful for smoothing solutions in time, and for re-identifying solutions for field and spectral window, as may be required in spectral line observations where doppler tracking is used on the target source, but not on the calibrater (and hence the spectral windows for each source are different). This function currently supports averaging of calibration tables containing Jones matrices with diagonal elements only (G, B, T). For B, the averaging is done for each channel separately (there is no channel averaging). Handling of tables with off-diagonal elements (D, F) will be supported in the future.

The fldsin parameter takes a vector of integers; the fldsout parameter must be a single integer (used for all fldsin) or a vector of integers, one for each in fldsin. They must both be specified.

The spwsin parameter takes a vector of integers; currently, only one spwout can be specifed (all spwsin will be averaged to this). They must both be specified. Use append=T to write more than one output spectral window to the same file. All input and output ids must exist in the measurement set.

Use the t paramater to set the interval over which solutions from the input field ids and spectral window ids will be averaged. Note that simple solution time-averaging can be achieved by making fldsin=fldsout and spwsin=spwout. If this parameter is negative (the default) the solutions are just copied.

Use the mode parameter to choose between 'RI'= averaging real and imaginary (coherently) or 'AP'= averaging amplitude and phase (incoherently). Use 'AP' to avoid reduction in amplitude if the solution phases drift appreciably during the averaging interval, t.

Example

c:=calibrater('3C273XC1.MS');
c.calave(tablein='3C273.gcal', tableout='3C273.gcal2', 
              fldsin=[1,2],spwsin=[2,3],fldsout=7,spwout=13,
              t=300, append=F, mode='AP')
c.done();

This example will average solutions from field ids 1 & 2 in spectral windows 2 & 3 in 300 second intervals and identifies the result as field id 7 and spectral window 13. The averaging is incoherent.