Jackson Labs PHASE STATION 53100A, User Manual

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PhaseStation 53100A User’s Manual V1.04 25-Apr-2022 93
accommodate a larger overall trend. Some additional usage examples can be found on
page 58.
Note that although only one Phase/frequency traces begin at zero ( z ) option appears
on the Trace menu, Timelab maintains separate copies of the associated preference
variable that retain the last change made in each of the respective views.
Show linear phase/frequency trend ( Ctrl-t )
When enabled, this option causes TimeLab to display a dashed line on unzoomed phase- and
frequency-difference traces to indicate the data’s linear trend.
The trend line is not displayed in magnified views, or when Trace → Show linear
phase/frequency residual ( r ) is enabled.
Use caution when interpreting drift figures derived from linear or quadratic trends .
Measurement traces that exhibit a large amount of variance relative to their overall slope – such
as might be obtained from comparisons of GPSDO or atomic standards -- can result in
numerically unstable solutions that vary randomly based on the number of points in the data
record.
Phase/frequency Y axis unlocked in zoom mode ( y )
By default, the Y axis in phase- and frequency-difference measurement graphs is
automatically scaled to accommodate the largest absolute value in all visible traces. The
peak magnitude is rounded up to the next decade, half decade, or quarter decade, then
mirrored to place zero at center scale. This approach allows the 10-division Y axis to be
labeled in “nice” multiples of 1, 2, or 5.
When zooming in with the mouse to magnify a portion of the visible trace(s), it’s
sometimes helpful to toggle the Y-autoscaling algorithm off by selecting
Phase/frequency Y axis unlocked in zoom mode ( y ) . This will have no effect on an
Figure 41: Viewing the trend line