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Basic Information on uvamp
Task: uvamp
Purpose: Annular averages a uv dataset in bins. Prints and plots results.
Categories: uv analysis
UVAMP reads a uv dataset, bins the data in annuli according to
uv distance and prints/plots vector averaged amplitude versus
uvdist. Statistical error bars and the expected amplitude for
zero signal are calculated.
Key: vis
The name of the input uv data set. No default.
Key: select
The normal uv selection commands.
Key: line
The normal uv linetype in the form:
line,nchan,start,width,step
The default is all channels (or all wide channels if there are no
spectral channels). The output will consist of only spectral or
wideband data (but not both). If spectral averaging is performed
(``width'' not equal to 1), then the output will be written as a
single spectral window.
Key: ref
The normal reference linetype, in the form:
line,start,width
The default is no reference line.
Key: stokes
If a value is given, uvamp will work with the specified
polarizations. Normally this should be set to stokes I if
the data includes polarizations.
Key: options
This gives extra processing options. Several options can be given,
each separated by commas. They may be abbreviated to the minimum
needed to avoid ambiguity. Possible options are:
'nocal' Do not apply the gains file. By default, UVAMP
applies the gains file in copying the data.
'nopol' Do not apply polarizatiopn corrections. By default
UVAMP corrects for polarization cross-talk.
'nopass' DO not apply bandpass corrections. By default
UVAMP corrects for the bandpass shape.
'ampscalar' Applies vector averaging to work out the
averaged visibility phase, but scalar averaging
to find the averaged visibility amplitude.
Key: bin
Number of bins, width of bins, and units of bin width. Up to 200
bins are allowed. The units for bin width may be either nsec or
klam. The default unit for bin width is nsecs.
Default values: 30,40,nsec
Key: offset
RA-Dec offset of desired phase center relative to phase center
of original uv dataset in arcseconds. Source of interest should be
at the phase center in the typical use of this program.
Default = 0.0,0.0.
Key: type
Calculate the amplitude and standard deviation for each bin based on
the real and imaginary components (total) or just based on the real
component (real). The "real" option is useful if your expected source
visibility is entirely real -- i.e. a point source or circularly
symmetric source at the phase center.
Possible options are "total" and "real". Default: total.
Key: device
Plot device name. If not specified, no plot is created.
Key: log
Log file name. Default is no log file.