Agilent Technologies J-BERT N4903B, User Manual, Page: 453 / 572

Jitter Frequency Test Points
You can specify the jitter frequency range to be used for the test, from 1 kHz up to
some hundred MHz. You can hence measure only a portion of the standard or points
outside the standard. Points outside the standard will always pass the test.
If a standard prescribes a certain range, for example from 2 kHz to 20 MHz, you
can select a checkbox to adjust the jitter frequency range to the loaded standard.
You can also specify the number of points to be measured. By default, the
measurement points are evenly distributed along the logarithmical frequency axis.
You may wish to measure the BER exactly at those frequency points where the
specified jitter amplitude changes. By selecting a checkbox, the distribution of the
measurement points can be adapted to the loaded standard, and the BER at the
points of interest will be measured.
Margin
It is possible to increase the jitter amplitudes of any standard by adding a margin.
This increases the stress on the device under test.
The margin is set in percent. A margin of 25%, for example, has the effect that each
amplitude value is multiplied by 1.25.
The following figure shows an example of a measurement with a margin of 50%
and sample point adaptation.
Jitter Tolerance Tests
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Agilent J-BERT N4903B High-Performance Serial BERT 453