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smavarfit

Section: User Commands (1)
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NAME

smavarfit - Analyse correlations of antenna gains and uv-variables.  

PERSON RESPONSIBLE

jhz/mchw  

CATEGORIES

uv analysis  

DESCRIPTION

SMAVARFIT is a Miriad task to analyse the correlations of antenna gains and uv-variables rooted from the Miriad task VARFIT. In addition to fitting the following:
         yaxis = slope *  xaxis +  intercept
        D(yaxis) = slope * D(xaxis) + intercept
where D() is the difference between succesive samples, SMAVARFIT provides an option of regression for the phases derived from the gains of two uvfiles. If either axis is an antenna gain, then SELFCAL must be run first and the axes are sampled at the interval used in SELFCAL. The rms and correlation coefficient are listed for each antenna.  

PARAMETERS

vis
The input UV dataset name. The antenna gains must first be derived for the selected linetype by the task SELFCAL with the desired averaging interval.
xaxis
xaxis can be antenna gain ``amplitude'' or ``phase'', or any uv-variables. The default is ``time''.
yaxis
yaxis can be antenna gain ``amplitude'' or ``phase'', or any uv-variables. The default is ``phase''.
log
Output log file. Default is the terminal.
device
Standard PGPLOT device, if plot of yaxis versus xaxis is wanted. Default is no plot.
nxy
Number of plots in the x and y directions. The default is 3,3.
xrange
The min and max range along the x axis of the plots. The default is to autoscale. Note that for "time" should be given in days.
yrange
The min and max range along the y axis of the plots. The default is to autoscale. Note that for "time" should be given in days.
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 uv-variable value for the refant is subtracted from each of the other antennas. Single valued variables, e.g. time, are unchanged. The default is to use the original gains and uv-variable values.
refant2
Reference antenna for cross correlation of gains and uv-variables. Compare the gains or uv-variables between antennas by fitting
        yaxis = slope * xaxis(refant2) + intercept
       D(yaxis) = slope * D(xaxis(refant2)) + intercept
where D() is the difference between succesive samples.
options
wrap Do not unwrap phase. xscale Re-scale xaxis = slope * xaxis + offset, where slope
              and offset are fitted w.r.t. xaxis(refant)
              The fit is written into the log file. E.g.
              yaxis=phase xaxis=tpower refant=4 log=tpscale
              results can be used in the task tpgains to correct
              tpower to a common Tsys scale.
yscale Re-scale yaxis = slope * yaxis + offset, where slope
              and offset are fitted w.r.t. yaxis(refant)
structure Replace yaxis with it's structure function:
                <{yaxis(i+k) - yaxis(i)}**2>
allan Replace yaxis with it's Allan variance:
                <{yaxis(i+2k) - 2*yaxis(i+k) + yaxis(i)}**2>
quad Fit yaxis = a + b*xaxis + c*xaxis**2
              where a and b are first derived from a linear fit.
              The fit is written into the log file. E.g.
              yaxis=tpower xaxis=tpower refant2=4 options=quad
              results can be used in the task tpgains to correct
              tpower to a common Tsys scale.
phareg do linear regression between phase1 and phase2 derived
             from the gain tables in uvfile1 and uvfile2, respectively:
             phase2 = slope * phase1 + offset


 

Index

NAME
PERSON RESPONSIBLE
CATEGORIES
DESCRIPTION
PARAMETERS

This document was created by man2html, using the manual pages.
Time: 18:35:38 GMT, July 05, 2011