Technical data

By default, the generator uses an internal clock source, or an
external clock multiplier (N4880A) for system board tests. Note that
the N4880A must be connected to the J-BERT and configured in
order to use it.
You can configure the analyzer's clock to external clock or internal
CDR.
Voltage Levels
You can set the voltage levels for every output independently. Note
that when moving any slider, the corresponding parameter will be
written to the hardware immediately. Otherwise, you'll have to click
the “Apply Levels” button. Note that the “Apply Levels” button also
applies the de-emphasis levels (if available).
You can also use the "Apply" button on the lower left corner of the
window to apply all parameters at once. Alternatively, you can click
the "Apply" command from the "Instruments" menu, or press F6 on
your keyboard.
De-Emphasis
If you connected an N4916B to the J-BERT, you can control the de-
emphasis and preshoot levels. The tabs let you select between three
different views:
• de-emphasis and pre-shoot in dB
• FIR tap coefficients
• emphasized and de-emphasized voltage levels
Note that when moving any slider, the corresponding parameter will
be written to the hardware immediately. Otherwise, you'll have to
click the “Apply” or “Apply Levels” button.
Jitter/SSC
Click “Jitter/SSC” to open the jitter window. Note that the
composition of available jitter sources is different for every spec
version and DUT type (which is selected in the main window in the
“PCI Express Physical Parameters” box).
Note that when moving any slider, the corresponding parameter will
be written to the hardware immediately. Otherwise, you'll have to
click the “Apply” button. When you change any parameter, e. g. enter
a new value into a text-box, the corresponding “Apply” button is
highlighted. This means that you have to apply in order to activate
your changes.
If you use calibration data, the compliance jitter values will use
calibrated levels. However, jitter parameters which are not covered
by the specification will not be calibrated.
19 N5990A-301 Getting Started Guide