User guide

How to View the Results
You can view data from accumulated measurements in several ways:
1
Click the Accumulated Results menu item from the Results submenu to view
the test results.
For easy comparison, the results of the current and previous accumulation are
listed here. See “Accumulated Measurements - Reference” on page 378 for
details on the reported values.
2
Examine the measurement log files on an external PC.
This allows to access all data for detailed processing and analysis on a PC.
Also, you can track the status of all indicators (such as DATA LOSS and CLK
LOSS) during the accumulation period. If you want to view results from an
accumulation period prior to the current and previous test, you can view the
respective log file, too.
How to Analyze the Results
Accumulated measurements can help you determine the cause of bit errors. Bit
errors can be caused by a variety of problems. In addition, instrument settings can
affect how errors are measured and displayed. The sync mode setting has the
greatest effect.
• Analyze the basic accumulated results and log files. Possible observations that
may occur are:
– Errors became constant (and remained constant for a period of time) or
number of errored 0's was greater than errored 1's, see “Constant Errors
(More Errored 0's than 1's)” on page 473.
– Errors were random, see “Random Errors” on page 474.
– Sync loss seconds were measured, see “Sync Loss Seconds” on page
475.
Accumulated Measurements - Reference
The Accumulated Results window presents data from the current and previous
accumulation period.
N O T E
Data from the current and all previous accumulation periods is available in the
measurement log files, if correctly set up.
This window contains a graph and five tables:
7 Evaluating Results
378 Agilent J-BERT N4903B High-Performance Serial BERT