[ Basic Info | User Guide ]
Basic Information on gpedit
Purpose: Edit the gain table.
Gpedit is a MIRIAD task which modifies calibration tables.
The input visibility file, containing the gain file to modify.
Normal uv data selection commands. See the help on select for
more information. Currently only antenna, time, and amplitude
selection is supported. The amplitude selection applies to the
gains, not the uv-data, and can be used to flag or replace bad
gain amplitudes. The default is to select everything.
The polarisation feeds affected (e.g. R, L, X or Y). Default is
This gives the complex-valued gain used in the `multiply' and
`replace' options (see below). It is given as an amplitude
and phase (in degrees). For example gain=2,90 produces a gain
with a amplitude of 2 and phase of 90 degrees.
The first two values specify the continuum solution, if there is
a gain table with n binned solutions, another n*2 values can be
specified. The default is 1,0 for all gains.
This gives extra processing options. Several values can be given,
separated by commas. Option values can be abbreviated to
The following options operate on the gains:
replace The existing gains are replaced by the value
given by the `gain' keyword. NOTE: If no other
options are given, the replace option is performed.
multiply The existing gains are multiplied by the gain
given by the `gain' keyword.
flag The existing gains are flagged as bad.
amplitude The phases of the existing gains are set to 0.
phase The amplitudes of the existing gains are set to 1.
scale The phase of the gains is multiplied by the factor
given by the `gain' keyword.
dup Convert a single-polarization gain table into a dual
invert The existing gains are inverted (1/gain, phase
negated) to allow undoing calibration that has been
applied to the uvdata with uvaver.
The following option operates on the polarization leakages:
reflect The existing leakages are made to possess a
symmetry: For each antenna, we make
DX = -conjg(DY).
zmean Subtract an offset, so that the mean leakage is 0.
The following option operates on the bandpass table:
extend Extend the bandpass table to cover the full range of
channels in the data. Use gain=0 to extend the
range by replicating the edge value and gain=1 to use
linear extrapolation of the edge values.
hanning Hanning smooth the bandpass. (Miriad actually uses
binomial smoothing when it claims to use hanning)
boxcar Boxcar smooth the bandpass (i.e., running average)
The smoothing width for hanning or boxcar smoothing of the
bandpass. Width will be increased to next odd number if even.
Default and minimum value is 3. Maximum is 33 for hanning,
and 257 for boxcar smoothing.
An optional second width parameter can be used to specify blocks
of channels to smooth, with no smoothing across block boundaries.
Default 0, is no blocks.
gpedit vis=cyga gain=14.4,90 select=ant(1,2) feeds=X
gpedit vis=cyga options=boxcar width=15
Generated by email@example.com on 26 Feb 2018