Agilent Technologies J-BERT N4903B, User Manual, Page: 148 / 572

Pattern Trigger Position
N O T E
This option is not available for alternate patterns.
Select this option to send a trigger signal that is synchronized to a certain position
in the pattern. Depending on the type of pattern currently loaded in the pattern
generator, you have to specify the trigger position either according to
Bit
Position
or
N-bit Trigger Pattern
:
•
Bit Position
If a memory-based pattern is loaded in the pattern generator, you have to
specify the bit in the pattern that sends the trigger. The bit position can be in
the range from 0 to Pattern Length - 1.
For pattern lengths that are divisible by 512 (such as 2^n PRBS patterns), the
trigger repetition rate is one pulse per pattern repetition.
Data Out
Trigger Out
Bit Pos.
A A A
For pattern lengths that are not divisible by 512 (such as some memory-based
patterns), a trigger signal is sent once at the corresponding bit when the pattern
reaches the 512-bit boundary. If, for example, the pattern is 384 bits long, a
trigger signal is sent every 4th pattern repetition.
Data Out
Trigger Out
Bit Pos.
A0 A1 A2
A A A A A A A A A A A A
If the bit position is outside the pattern (i.e. the entered number greater than
the pattern length - 1), the entry is adjusted to the pattern length - 1, i.e. the
trigger is set to the last bit in the pattern. If you load a pattern that is shorter
than the entry in this field, the trigger will be set to the last bit in the pattern.
• N-bit Trigger Pattern
This option is used for hardware-generated PRBS patterns. You can specify a
pattern with n bit length. A trigger pulse is sent when this pattern is found in
the PRBS. The trigger repetition rate is one pulse per 512 pattern repetitions.
Example:
Pattern length: 2^7-1 (127) bits
N-bit pattern: 1110001
4
Setting up the Pattern Generator
148 Agilent J-BERT N4903B High-Performance Serial BERT