User guide
N O T E
Length is related to master channel (Data Out) while the other channel (Aux Data)
will always follow this length.
• Trigger: Refers to the pattern generator's Trigger/Ref Clock Out port. If the
Trigger/Ref Clock Out is set up to generate a divided clock pulse, the block
setting is ignored.
But if the Trigger/Ref Clock Out is set to "Sequence Trigger" and the block to
TrigOn, a trigger pulse is generated whenever the block starts or restarts. No
trigger is sent if the block is set to TrigOff.
See “Trigger/Ref Clock Output - Procedures” on page 145 for information on
how to set the mode of the Trigger/Ref Clock Out port.
Default is one overall endless loop for the whole sequence.
• B
n
, B
m
: Define the start and end block of a user-defined loop.
Loops always define the transition from the end of a block to the beginning of
the same or a previous block. It is not possible to jump into an existing loop. It
is also not possible to specify loops within loops (exept the default overall loop).
• Loop end condition: Default is an INFinite (endless) loop. Other options are:
– AuxInHi | AuxInLo: Loop continues until Auxiliary Input is high or low.
– AuxInRising | AuxInFalling: Loop continues until Auxiliary Input receives a
rising or falling edge.
– Manual: Loop continues until the Break button is clicked.
– Counted loop: Loop repeats a specified number of times.
Sequence Mode Characteristics
When a sequence is executed, the pattern generator is in "Sequence Mode".
This mode differs from usual "Pattern Mode":
• Pattern-related triggers cannot be generated. In sequence mode, the Trigger/
Ref Clock Out port can produce either a continuous pulse (a fraction of the
current clock pulse) or a trigger spike at the beginning of each block that is set
to TrigOn. The duration of that spike depends on several conditions and is
therefore undefined.
• Software-generated PRBS with polynomial 2^n cannot be referenced in a
sequence.
• If several PRBS patterns shall be included, all have to use the same polynomial.
• Every sequence has to be downloaded to the pattern generator before it can
be executed.
3 Setting up Patterns
98 Agilent J-BERT N4903B High-Performance Serial BERT
LOOP Options