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Version 1.9 Build 1488

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iramcalibrater.phase - Function

	Package	alma
	Module	alma
	Tool	iramcalibrater

perform phase calibration on the data

Synopsis
phase(fieldnames, freqgrp, refant, phasetransfer, rawspw, npointaver, phasewrap)

Description
This function performs a phase calibration using the selected calibration sources and spectral window ids. Previously bandpassed calibrated data, averaged in the spectral domain, are used to find the phase solution. The solutions are antenna based cubic splines.

A plot of the solution is returned to the disk as a postscript file with a name consistent with the ms file name and bands/sidebands solved for.

For less-than-well-behaved data with phasewraps, the npointaver and phasewrap parameters may be used to tune the phase tracking algorithm. npointaver sets the number of consecutive time points that are averaged for comparison with the next point to see if it has slipped a cycle. phasewrap is the phase difference required in the comparison to indicate a cycle slip. When a cycle slip is detected, the current point and all future points will be shifted by + / - 360 before the solution. Such slip corrections will accumulate for every detected slip. For well-behaved data, the defaults should be adequate.

Returns
Bool

Arguments

fieldnames		Field names of calibrators to be used
		Allowed:	Vector of Strings
freqgrp		frequency group to solve for phase
		Allowed:	'3mm-LSB' || '3mm-USB' || '1mm' || '1mm-LSB' || '1mm-USB'
		Default:	'3mm-LSB'
refant		Reference antenna
		Allowed:	Int
		Default:	1
phasetransfer		type of transfer for 1mm solution
		Allowed:	'raw' || 'curve' || 'none'
		Default:	'raw'
rawspw		spectral window used in case of raw phase transfer
		Allowed:	Int
		Default:	-1
npointaver		Number of consecutive time points averaged for phase tracking
		Allowed:	Int
		Default:	10
phasewrap		Phase difference that indicates a cycle slip in phase tracking
		Allowed:	Quantity
		Default:	'250deg'

Example

myic:=iramcalibrater('10feb97-g067.ms')      
myic.phcor(F)
myic.rf(fieldname='0528+134', freqgrp='3mm-LSB')
myic.phase(fieldnames=['0528+134', '0415+379'], freqgrp='3mm-LSB')
myic.rf(fieldname='0528+134', freqgrp='1mm')
myic.phase(fieldnames=['0528+134', '0415+379'], freqgrp='1mm',
phasetransfer='raw', rawspw=3)
myic.done()

In the example above we used 0528+134 to do the bandpass calibration and 0528+134 and 0415+379 to do the phase calibration at 3mm. Then the bandpass is done on the 1mm (both side bands) with a phasetranfer from the spw=3 as raw phase reference at 3mm.