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Setting up the Error Detector - Concepts
Agilent J-BERT N4903B High-Performance Serial BERT
User Guide
5
Setting up the Error Detector
The error detector analyzes an incoming bit stream, compares it to the expected
pattern, and locates any inconsistencies. The error detector requires the following
settings to work correctly:
•
The expected pattern
The error detector needs to "know" which data to expect so that it can detect
bit errors.
•
Correct input and output terminations to the DUT
This ensures that your DUT cannot be damaged due to incorrect terminations.
•
Correct clock frequency
Required to recognize the bit rate in the data stream.
•
Appropriate sampling point
The sampling point defines where the error detector tries to differentiate
between 0s and 1s in the data stream. This is necessary so that the error
detector recognizes the data bits correctly.
•
Synchronization to the incoming pattern
The expected pattern must be synchronized to the incoming pattern so that the
error detector can find any discrepancies.
The error detector provides the following functions to enable you to perform tests:
•
Automatic pattern synchronization
The error detector shifts the incoming data stream bitwise to match it to the
expected data pattern. A correct BER can only be measured with matching
patterns.
•
Error accumulation
You can specify whether a test runs for a specified time or until a specific
number of errors has occurred. This lets you carry out longer tests while logging
the results to a file.
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