Jitter High Pass Filter (Hpf) Selection; Trigger Mode; Jitter Waveform Mode; Eye Pattern Setup - Videotek TVM9100PKG Installation And Operation Handbook

General Operation

Jitter High Pass Filter (HPF) Selection

Because jitter on the data can develop from many sources and have a unique frequency
distribution, the bandwidth of the sampling clock recovery circuit will affect the
displayed jitter if the frequency of the jitter is within the bandwidth of the clock
recovery circuits. Above the loop bandwidth, the loop has no effect on the jitter. While
within the bandwidth, the apparent jitter displayed will be satisfied by the loop
response.
To access the jitter high pass filter selections, press and hold the EYE button until the
Eye Pattern pane menu appears. Select between 10 Hz, 100 Hz, or 1000 Hz is high
tally. When 10 Hz, 100 Hz, or 1000 Hz is selected, the –3 dB response points only
allow jitter above the selected filter frequency. This is useful with estimating the effects
of jitter on clock recovery circuits of similar bandwidths in receivers and inferring the
sources of the observed jitter based on frequency components present. Changing this
selection in the Eye Pane will change the Jitter selection in the Jitter pane (just as
changing the selection in the Jitter pane will change the selection in the Eye Pane)
unless 10 kHz or 100 kHz is selected in the Jitter pane.
Selecting 10 kHz or 100 kHz will provide more Jitter filtering in the Jitter pane, but the
Eye pane will not mirror the Jitter filtering selection. As long as 10 kHz or 100 kHz is
selected in the Jitter pane, the filtering selection will not coincide with the filter
selection in the Eye pane. Only when the selection in the Jitter Pane returns to 10 Hz,
100 Hz, or 1000 Hz will the Jitter pane and the Eye Pane mirror filtering selections.

Trigger Mode

The TRIGGER MODE submenu is located in the EYE PATTERN SETUP menu.
Within the TRIGGER MODE submenu, two modes of operation are available:
• OVERLAY (3 Eye SD/HD)
• 10/20 EYE (10 Eye for SD/20 Eye for HD)
Distortions in Overlay mode are all displayed in the visible eye locations of the Eye
Pattern display, giving a more easily observed display of the total jitter. Overlay
displays three eye openings.

Jitter Waveform Mode

When the Jitter Waveform pane is first displayed in the selected pane, the Jitter is
shown as the plot of the eye jitter vs. time. The Jitter Waveform Mode is used to
change the display from the plot of the eye jitter vs. time to the plot of the jitter vs.
frequency.

Eye Pattern Setup

Press the ENT button to access the global Eye Pattern setup menu. For more
information on the global Eye Pattern Setup menu see Section 4.
60 TVM Series Installation and Operation Handbook
Copyright © 2008, Harris Corporation