Omega 1002 - Manual (Page 37)

The A/D trigger logic can initiate an A/D conversion upon an
external trigger. Valid external trigger signals must be TTL compatible
and meet minimum pulse width requirements. The requirements are shown
below:
t
re
t
du
External trigger
Symbol Name Minimum Maximum
T
du
Duration time 40ns ∞
T
re
Recover time 100ns ∞
Note: The OME-PCI-1002 is designed only for time sensitive triggers
(trigger is dependent only on the time of the falling edge of
signal). For a level sensitive external trigger (trigger is dependent
on the level of the input signal), the user can build the following
external circuit the OME-PCI-1002:
DAC OME-PCI-
1002 D/O
Input Signal
Comparator
TTL buffer
External
Trigger
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