Agilent Technologies N4906B Serial BERT User Manual page 150

Evaluating Results
Accumulated/Actual Button
Error Count/Accum Error Count
150
How to Analyze the BER Results
To analyze the behavior of your device, you can do the following
modifications to the test setup and monitor the effect on the resulting
BER:
1 Add errors to the data stream. See "Error Addition/Insertion –
Procedures" on page 72 for details.
2 Use alternating patterns to switch between different data streams.
See "Pattern Alternation – Procedures" on page 77 for details.
3 Adjust the parameters of the output port of the pattern generator,
as described in "Input and Output Ports – Procedures" on page 58.
4 Manually move the sampling point. See "Sampling Point Setup –
Procedures" on page 101 for details.
5 Make adjustments to your device.
This can be used to see how changes to your device affect the BER.
You can determine what adjustments improve or degrade the BER.
Instantaneous Measurements – Reference
This section describes all elements of the BER Results window and the
various status indicators:
BER Results Window
This window displays the actual (BER) or cumulative (AccumBER)
BER results:
• The BER is the current BER, calculated upon a period of 200 ms.
• The AccumBER shows either the accumulated BER of the current
accumulation, or—if no accumulation is running—the results of the
most recent accumulation.
This enables you to monitor real-time BER behavior as you do things
such as to manually adjust the sampling point, to add errors, or to
make adjustments to your device.
Click this button to toggle between BER or AccumBER results.
This area displays the actual error count or cumulative error count.
NO TE The BER bar below the main menu bar also displays the actual BER.
You can drag the small yellow alarm threshold mark to change the BER
Alarm Threshold.
Agilent N4906B Serial BERT, User's Guide, October 2005
Instantaneous Measurements