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Basic Information on phatrans
Task: phatrans
Purpose: Transfer Phase correction and create new gain table.
Categories: calibration
PhaTrans is a Miriad task to transfer phase correction from
gains derived from a vis data observed at a lower frequency (freq1)
to the phase corrections for the vis data observed simultaneously at
a higher frequency (freq2).
The phase transfer uses a linear relation between the two
frequnecies (freq1 and freq2):
pha_freq2 = slope * pha_freq1 + intercept
where slope and intercept can be read from a slope
table determined using varfit based on observations of a strong
point source at the two frequencies, simultaneously.
There are options to use slope = freq2/freq1 and intercept=0, or
to use users input for the slope and intercept.
Key: vis
The name of the three input UV datasets.
1. vis data at the lower frequency. The antenna gains must first be
derived by the task SELFCAL with the desired averaging interval.
2. vis data contains the slope table.
3. vis data at the higher frequency. The transferred new gains table
is created.
Key: refant
Reference antenna for gains and uv-variables. If refant.ne.0 then
the gain of this antenna is set to cmplx(1.,0.). The
other antenna gains are then relative to the reference antenna.
The default is to use the original gains and uv-variable values.
Key: phratio
Phase ratio for slope when options=uratio;
The default is to use the frequency ratio.
Key: phoffset
Phase offset (in degree) for intercept when options=uratio
or when options=fratio;
The default is 0.
Key: options
wrap Do not unwrap phase.
fratio Use the frequency ratio of freq2/freq1 for slope and
intercept=0.
uratio Use the phase ratio from user's input (phratio).
Default uses slope table in the input file 2.