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Unwrapping triple phases

There are three unwrapping algorithms available under CALIBRATEVISIBILITYTRIPLE. For the first two, REWRAPTRIPLE and DEWRAPTRIPLE, you have to have calibrator stars selected first, since they unwrap only the data for these stars (for the time being). Rewrapping here shall mean the rotation of the complex visibility by a specified angle so that the entire range of phases fits into the interval $[-180,+180]$ degrees. The the phases are recomputed, and backrotation is applied to the complex quantities, but merely subtracted from the phases. If the phase is wrapping more rapidly, one should plot the (calibrated) triple phase, and fit a low order polynomial to a stretch which does not wrap (use FIT). The fit parameters are passed to the unwrapping algorithm, which removes it from the data and then removes also the resulting steps. The fit is then reapplied to the data. The manual unwrapping utility, MANUALUNWRAP, will allow the user to place a box into a plot of phase vs time or channel, and the data inside will be rotated $+360$ or $-360$ degrees, as specified. No calibrator stars need be specified for this operation. Note that in this case the calibrated phase has to be plotted, since this is the phase which is unwrapped!


next up previous contents
Next: Astrometry Up: Calibrate data Previous: Calibrating amplitude errors   Contents
Christian Hummel 2009-10-20