User guide

User Patterns
User Patterns - Concepts
User patterns are user-editable patterns that are written to the Serial BERT's
memory for pattern generation (see “How does the Serial BERT Generate
Patterns?” on page 61 for details). User patterns can contain up to 32Mbit of any
arbitrary data pattern. They may be generated by the Serial BERT software or
defined in a pattern file and loaded into the memory. The Serial BERT reads the
memory bit by bit, and generates the output accordingly.
The following topics explain how the Serial BERT works with user patterns, and
also explain how user patterns are generated.
N O T E
The way software-generated patterns (distorted PRBS, PRBN) are output is
identical to that of user patterns: The patterns are written to the memory, and the
output is generated from there. Some of the information in these topics covers how
the patterns are actually generated, and thus also applies to software-generated
patterns.
When to Test with User Patterns
Creating or editing patterns is necessary for quality testing because different
patterns present different data loads to the device. This can cause variations in
the bit error ratio. With user patterns, you can define exactly the pattern used in
the test.
Supported Pattern Types
The Serial BERT can import the following pattern types:
• HP/Agilent 71612A series patterns (*.dat file type).
• Patterns (binary, hex, symbol, "01") saved as ASCII files by the Serial BERT or
the Agilent 86130 (*.ptrn and *.txt file type).
These are described in detail in “Pattern File Specifications” on page 66.
The Serial BERT can save files as either *.dat, *.ptrn or *.txt files.
N O T E
Downloading a text format pattern into your instrument may take significantly longer
than a binary pattern.
Setting up Patterns 3
Agilent J-BERT N4903B High-Performance Serial BERT 65