Agilent Technologies J-BERT N4903B, User Manual, Page: 162 / 572

further configuration possibilities. This pattern is sent as long as the output
port is enabled.
See
“Setting up Patterns - Concepts” on page 61 for more details.
• Alternating patterns consist of two patterns, one of which is pattern A (the A
half), the other is pattern B (the B half). Both patterns are of equal length, each
up to 16Mbit.
The
Alternate Pattern Control
dialog box lets you control when which pattern is
sent. See “Pattern Alternation - Procedures” on page 162 .
When to Use Alternating Patterns
Alternating patterns can be used:
• To systematically insert errors in the bit stream at particular positions.
The error detector expects pattern A only. If you set up pattern B so that there
are only minor differences, when you run the test, the error detector will detect
the changed bits as errors.
• To see how long it takes your DUT to settle.
You can set up an easy-to-process output stream as the standard pattern, and
a difficult output stream as the alternate pattern (for example, all 0s for the
standard pattern, and alternating 1s and 0s as the alternate pattern). You can
then track how long it takes for your DUT to recover after the alternate pattern
has been sent.
Pattern Alternation - Procedures
The
Alternate Pattern Control
dialog box controls how the output stream switches
between the standard pattern and the alternate pattern.
You have the following possibilities for setting up alternating patterns:
Setting Up a Periodical Output
To configure the pattern generator to generate periodical data output:
1 Click
Alt. Pattern and Aux In
menu item from the
PG Setup
submenu to open
the
Alternate Pattern Control
dialog box.
2 Select one of the following options:
4
Setting up the Pattern Generator
162 Agilent J-BERT N4903B High-Performance Serial BERT