Agilent Technologies N4906B Serial BERT User Manual page 154

Evaluating Results
154
3 To begin accumulation, press the Start Accum button on the front
panel.
This causes the following events:
• If Prompt for File Name has been selected during setup, you will be
asked to enter a name for the log file before accumulation begins.
• The data display in the Accumulated Results window is reset.
• The recording of data to the measurement log file is reset.
How to Stop Accumulated Measurements
If you specified a single or repeat test, the test runs until the specified
end condition is reached. If you selected a manual test, it will run until
you stop it manually.
♦ Press the Stop Accum button on the front panel to stop the test
immediately.
NO TE Errors are only counted when the signal at the Gate In port is low.
How to View the Results
You can view data from accumulated measurements in several ways:
1 Press the Accumulated Results icon in the Results menu 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 155 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.
Agilent N4906B Serial BERT, User's Guide, October 2005
Accumulated Measurements