Instruction manual

Controlling image capture
PIKE Technical Manual V3.1.0
158
Jitter at start of exposure
The following chapter discusses the latency time which exists for all CCD
models when either a hardware or software trigger is generated, until the
actual image exposure starts.
Owing to the well-known fact that an Interline Transfer CCD sensor has both
a light sensitive area and a separate storage area, it is common to interleave
image exposure of a new frame and output that of the previous one. It makes
continuous image flow possible, even with an external trigger.
The uncertain time delay before the start of exposure depends on the state
of the sensor. A distinction is made as follows:
FVal is active Æ the sensor is reading out, the camera is busy
In this case the camera must not change horizontal timing so that the trigger
event is synchronized with the current horizontal clock. This introduces a
max. uncertainty which is equivalent to the line time. The line time depends
on the sensor used and therefore can vary from model to model.
FVal is inactive Æ the sensor is ready, the camera is idle
In this case the camera can resynchronize the horizontal clock to the new
trigger event, leaving only a very short uncertainty time of the master clock
period.
Model Camera (while FVal) Camera idle
Pike F-032 ± 4.9 µs ± 8.3 ns
Pike F-100 ± 8.2 µs ± 8.3 ns
Pike F-145 ± 16 µs ± 8.3 ns
Pike F-210 ± 14.25 µs ± 8.3 ns
Pike F-421 ± 15 µs ± 8.3 ns
Table 67: Jitter at exposure start
Note
L
• Jitter at the beginning of an exposure has no effect on
the length of exposure, i.e. it is always constant.