User guide

The example above was done for a target BER measurement of 10
-3
and a
confidence level of 95%. As a rule of thumb, this requires to measure approximately
3 times the number of bits given by the target BER.
The sampling frequency of the 86100A is specified with 40kHz, which gives a
sampling period of:
The timing interval resolution is given as:
The time base needs to be set to:
The number of waveforms that are required to be measured for achieving the
confidence level of 95% is:
Each measured waveform contains the following number of samples:
The overall required measurement time can be estimated as:
The above formula shows that choosing
as 62.5fs leads do longer measurement times than required. So it is safe to assume
the highest possible resolution for this estimation.
In the example above the following values have been used:
• #bits = 4
•
Target BER = 10
-3
• Data Rate = 14.2 Gb/s
This gives a time base setting of 28.2ps and a measurement time of 338 seconds.
Solving Problems 9
Agilent J-BERT N4903B High-Performance Serial BERT 489
Notes on the measurement duration