JYTEK USB-62405, Руководство пользователя

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36 Operation
Post-Trigger Acquisition Mode (no retrigger)
Post-trigger acquisition is indicated in applications where data is to
be collected after a trigger event, as shown.
Figure 3-9: Post Trigger without Retrigger
Pre-trigger Acquisition (no retrigger)
Collects data before the trigger event, with acquisition starting once
specified function calls are executed to begin the pre-trigger opera -
tion, and stopping when the trigger event occurs. If the trigger event
occurs after the specified amount of data has been acquired, the sys -
tem stores only data preceding the trigger event by a specified
amount, as shown. Note that N must be equal to or less than 8k sam -
ples for all analog input channels.
Figure 3-10: Pre-trigger Mode Operation (valid trigger only)
Time
Ɣ Operation
start
Trigger
N samples Data
Ɣ
Trigger Event Occurs
Ɣ
Acquisition start
Ɣ Acquisition stop
Ɣ Begin to transfer data to system
Time
Ɣ Operation start
Ɣ Acquisition start
Trigger
Data
Ɣ
Trigger Event Occurs
Ɣ Acquisition stop
Ɣ Begin to transfer data to
system
N samples
This data is
discarded.
Only acquired N
samples will be
transferred back to
system.