Photron FASTCAM ultima APX-i2, Руководство по оборудованию

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FASTCAM-ultima APX-i2 Hardware Manual
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4.5.6. RANDOM RESET Mode
This section describes the principle of operation of the RANDOM RESET mode in
comparison with the RANDOM and START mode. To simply put it, the RANDOM
RESET mode is a mode of recording operation that has been devised to improve the
accuracy of temporal relationship between the timing of trigger input and that of start of
recording by resetting the recording timing, i.e. vertical sync, at the input of a trigger.
The following figure is a visual presentation of the basic idea of the RANDOM RESET
mode.
Trigger Signal (TRIGGER IN)
■ RANDOM Mode Operation
Record Timing Signal
( Vertical Sync Signal)
Frames to be Recorded
① ② ③ ④ ⑤
Record Timing Signal (Vertical Sync Signal) is not changed by TRIGGER IN signal.
The frame being exposed when trigger signal comes in is recorded as first frame.
Slight offset between trigger and frame timing occurs.
■ RANDOM RESET Mode Operation
Record Timing Signal
(Vertical Sync Signal)
Frames to be Recorded ① ② ③ ④
Record Timing Signal (Vertical Sync Signal) is reset by TRIGGER IN signal.
The above figure shows the difference in timing of trigger input and start of recording
between the RANDOM (or START) mode and RANDOM RESET mode.
In the RANDOM or START mode, the record timing signal (vertical sync) advances
regardless of the timing of trigger input as shown in the above. Because of this fact, the
recording start time of the first frame may be slightly brought forward, up to about 3/4 of
a framing cycle, depending on when the trigger is given, and there is no knowing how
much the offset may be.