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New iStar ICCD
Pre-Acquisition Setup - Image Intensifier
5.5.3 - Fast external
Fast External Trigger i
s for the most part identical to external trigger. It differs in only one key aspect. In fast external
trigger the camera will not wait for a sufficient number of keep clean cycles to have been completed to ensure the image
area is completely clean of charge before accepting an external trigger event, but instead will allow a trigger event to
immediately start the acquisition process after performing a ‘1 vertical-1 horizontal, keep clean cycle’. As a result, fast
external trigger allows a higher frame rate than standard external trigger.
The Arm is set low and the Fire pulse high approximately one ‘keep clean cycle’ later. If one is monitoring on the
oscilloscope the external trigger with respect to the Fire pulse, the jitter of one ‘keep clean cycle’ will be seen. Note that
the intensifier will open in response to that first external trigger and the jitter in the Fire pulse is not important. Also note
that output A/B/C are available to offer lowest jitter between them and the external trigger and gate pulse.
The timings are the same as in external trigger mode, except that by removing the keep clean cycle the CCD can be
triggered earlier as shown by the Arm waveform below.
External Trigger
Fire
gate Monitor
ARM
