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3�5 Trigger Modes
There four trigger modes working with trigger sources to initiate different data acquisition
timing when a trigger event occurs. They are described in this section.
3.5.1 Post-trigger Acquisition
Use post-trigger acquisition when you want to collect data after the trigger event, as
illustrated in Figure 3-11.
Time
Operation
start
Trigger
N samples
Data
Trigger Event Occurs
Acquisition start
Acquisition stop
Begin to transfer data to system
Figure 3-11: Post-trigger Acquisition
3.5.2 Pre-trigger Acquisition
Use pre-trigger acquisition to collect data before the trigger event. The acquisition starts
once specified function calls are executed to begin the pre-trigger operation, and it stops
when the trigger event occurs.
If the trigger event occurs after the specified amount of data has been acquired, the system
only stores the data before the trigger event with specified amount, as illustrated in Figure
3-12.
Time
Operation start
Acquisition start
Trigger
Data
Trigger Event Occurs
Acquisition stop
Begin to transfer data to
system
N samples
These data will be
discarded.
Only acquired N
samples will be
transfer back to
system.
Figure 3-12: Pre-trigger Mode Operation
