Agilent Technologies J-BERT N4903, User Manual

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patterns delivered with the Serial BERT. You can easily define your own
patterns for any special requirements.
The Serial BERT can also generate various PRBS 2^n patterns with a
range of polynomes from 7 to 23. These patterns can be further modified
by setting special mark densities (ratio of 1's to total bits) or by defining
the zero substitution.
It is possible to combine several patterns in a sequence. A sequence
consists of up to four blocks that can be looped. Each block can generate
a pause signal (constant 0 or 1), a divided clock, a 2^n -1 PRBS, or a user
pattern.
What Patterns are Available?
The Serial BERT offers various industry standard and customized
patterns for many BER testing scenarios.
The following graphic illustrates what patterns are available on the
Serial BERT. Note that there are two main branches, corresponding to
the hardware-generated and memory-based patterns, and the memory-
based patterns are further broken down into software-generated
patterns and user patterns.
Pattern Family Tree
User Patterns
Hardware-Generated
Patterns
Custom User
Patterns
Example Patterns
in C:\N490 X \Pattern\Demo
2^n-1 PRBS
FDDI
Fiber-Channel
Gigabit Ethernet
2^n PRBS
2^n PRBS
Mark Density
SDH SONET
Industry Standard Pattern or
modified Industry Standard Pattern
PRBS
Software-Generated Patterns
Zero Substitution Mark Density
Memory-Based Patterns
See “Example Patterns” on page 33 for a complete listing of the
example patterns.
What is PRBS?
The most common type of industry-standard pattern is the Pseudo-
Random Binary Sequence (PRBS). PRBSs have a number of desirable
properties, including the ability to simulate random data with a
balanced number of 1's and 0's.
2
Setting up Patterns
24 Agilent J-BERT N4903 High-Performance Serial BERT
Software-Generated Patterns
Sequences