Agilent Technologies J-BERT N4903B, User Manual, Page: 70 / 572

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Implications of Using Memory-Based Patterns
There are several implications to the way Serial BERT handles memory-based
patterns, a few of which are:
• If you set up an alternating pattern where pattern B is a replica of pattern A
except for the addition of one error, and the pattern is an odd number of bits
long, the error will be repeated 512 times when B is sent (because pattern B
is sent 512 times before switching back to A).
• If you want to send a periodic pattern, you only have to define a single repetition.
For example, if you want to send alternating 1's and 0's, you only have to define
the first two bits. This pattern is automatically loaded 256 times to fill up a
complete block of RAM.
• If you set up a trigger to be generated whenever a pattern is sent, the trigger
is sent whenever all blocks that store this pattern have been sent (and not
every time the pattern is sent).
So, for example, if you have a standard pattern that is 384 bits long, this pattern
must be loaded into the memory four times to reach the 512-bit boundary. A
trigger would then be generated every 4x384bits, or 1536bits.
Example Patterns
The Serial BERT provides a set of example user patterns. These patterns mimic
real data packets and standard stress patterns.
The directory for the example user patterns is:
C:\<instrument model>\Patterns\Demo
C A U T I O N
Any changes you make to the patterns in this folder are non-recoverable (there is
no backup folder). To avoid inadvertent changes, it is recommended that you copy
the demo files to a different directory before loading them.
For a complete list of available patterns and their description, see
C:\<instrument model>\Patterns\Demo\Description.pdf
For more information on the recommeded pattern for specific purposes, see
“When
to Use Which Pattern?” on page 64 .
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Setting up Patterns
70 Agilent J-BERT N4903B High-Performance Serial BERT