User guide

As the bathtub borders are not uniform (both have two edges), the linear derivative
(the jitter) will show two peaks:
If you switch to linear scale and enable the marker, you can see its bell shape.
You can measure the random jitter distribution of each peak as well as the distance
between the peaks, which means the deterministic jitter.
You can also use the marker with logarithmic scale. In this case, it appears as a
parabolic curve:
A Gaussian marker is used when the dBER vs. Threshold Graph is displayed. This
graph shows the relationship between the decision threshold and the absolute
values of the derivative of the bit error rate (dBER/dTh). A linear scale reveals the
distribution more clearly than a logarithmic scale (see “dBER vs. Threshold Graph”
on page 274).
In the example below, μ (Mu) and σ (Sigma) will be the same as the Level and
Standard Deviation results calculated by the measurement.
6 Advanced Analysis
240 Agilent J-BERT N4903B High-Performance Serial BERT
Output Levels measurement