User guide

Table 26
Parameter Description Definition
Optimal Sample Point
Delay
The average of the left (A)
and right (B) bathtub/BER
threshold intersections.
(A+B)/2
Phase Margin The period of time where
the bit error rate is lower
than the BER threshold.
B-A
The A and B values are the left and right intersections of the bathtub curves with
the BER threshold. Obviously, all values change if the BER threshold is modified.
The following illustration shows an example for a measurement.
N O T E
This graphical view is not available in the measurement software.
The jitter measurement parameters are defined in the following list.
N O T E
All jitter measurement parameters (except the Total Jitter RMS and Total Jitter
Mean) change with the BER threshold.
• Total Jitter RMS
The average of the left and right jitter histogram root mean squared values.
• Total Jitter Peak-to-Peak
Peak-to-peak value for total jitter. Calculated as the pulse period (unit interval)
minus the Phase Margin.
6 Advanced Analysis
260 Agilent J-BERT N4903B High-Performance Serial BERT
Jitter Measurement Parameters