User guide

With this checkbox you can determine whether both pattern generator and error
detector use the same data pattern.
If you clear this checkbox, the Error Detector Pattern tab appears, where you can
select a different pattern for the error detector.
The checkbox is automatically cleared when you load a user-defined sequence to
the pattern generator. See “Sequence Mode Characteristics” on page 98 for
details.
You can choose between the following types of patterns:
•
User Pattern from File
With this option, you can load a pattern that is stored in a file. Use the
Browse button to select the desired file.
•
Memory User Pattern
The Serial BERT supports 12 so-called memory slots for storing user patterns.
The slots are stored in files named Upat1.ptrn to Upat12.ptrn . To load a pattern
that is stored in one of these memory slots, choose this option and select the
desired slot from the list.
•
2^n -1 PRBS
Select this option to use a hardware-generated pattern of length 2^n-1. See
“How the Hardware Generates PRBS” on page 94 for details.
•
2^n PRBS
Select this option to use a memory-based pattern of length 2^n.
•
Mark Density PRBS
Use this options to generate memory-based 2^n PRBS patterns with specified
mark densities. Select the desired value from the list. The available values are
1/8, 1/4, 1/2, 3/4, and 7/8.
•
Zero Sub PRBS
Use the Zero Substitution function to insert a longer row of zeros into a memory-
based 2^n PRBS pattern. The length of the zero row can be freely specified up
to the length of the pattern.
You can select the pattern size according to your needs. The pattern lengths
available depend on the type of signal you have selected.
Enable this checkbox if you wish to use a user-defined sequence. The patterns
used in a sequence are defined in the Sequence Editor (see also “User-Defined
Sequences - Concepts ” on page 96).
3 Setting up Patterns
90 Agilent J-BERT N4903B High-Performance Serial BERT
Error Detector Pattern Tracks the
Pattern Generator Pattern
Pattern Types
Pattern Size
Sequence