OmniTek Ultra 4K Tool Box, User Manual

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------------------------------- Physical Layer: Eye & Jitter --------------------------------
Ultra v2.0a User Guide
S-12
Setting the range
To set the range of jitter amplitudes displayed:
 Set the Range option included in the right-hand panel when the Jitter Histogram display is
selected.
To adjust the range shown to fit the measured distribution:
 Take the
Autofit
option offered on the Button Bar when the Jitter Histogram display is
selected.
Resetting the display
The Jitter Histogram is determined from all the values for the jitter measured since the
measurement started. A button is provided on the Button Bar to allow the user to clear the current
history and start the determination of the histogram afresh.
To start the determination of the Jitter Histogram afresh:
 Select Clear History from the Button Bar shown when the Jitter Histogram is selected.
S.3.5 Jitter Waveform
(Requires PHY_ADV)
The Jitter Waveform display comprises a trace of the jitter detected in the data carrier signal, shown
as a graph of amplitude against time (in a choice of colours). The jitter displayed is the result of
passing the signal through a selected high-pass filter. The pass frequency of this filter is selectable
between 10Hz and 100kHz. A V Gain setting is also provided through which you can set the
scaling applied to the vertical axis of the trace.
Figure S-13: Jitter Waveform
The way to interpret the Jitter Waveform is to work in sequence through the different filter
frequencies that are available, comparing the distributions that are shown at each stage to
determine the waveband(s) in which jitter energy is chiefly concentrated. (The location of jitter
energy in a particular waveband is indicated by large changes in overall jitter energy and/or the
appearance/ disappearance of periodic structures within the display as you move through the
different filters.)