User guide

The figure above shows the absolute power scale and values as calculated by the
FFT. You can also calculate relative values.
Relative values can be normalized to either the total power (True Relative) or to
the power of a selectable frequency bin (Relative).
The following figure shows an example where the scale and the power values have
been normalized to the power measured at 1 MHz.
When you set the power values to relative, this changes not only the graphical
scale but also the calculated results. You can thus calibrate the power values to
any reference.
The Noise Threshold can be moved with the mouse (or your finger, if you are
working directly on the Serial BERT). It can also be set on the View page of the
Properties dialog.
This threshold is used to separate between total power and noise power. All
components below the Noise Threshold are considered noise. When the threshold
is changed, the calculated Noise Power values change.
If desired, change the Number of Top Frequencies to Show. This determines the
number frequency/power pairs in the numerical section. Up to 16 pairs can be
calculated and displayed.
Graph Tab
On the Graph tab, you can use the several options to optimize the graphical display
according to your needs.
6 Advanced Analysis
358 Agilent J-BERT N4903B High-Performance Serial BERT
Absolute vs. relative values
Noise Threshold