Specifications

Table Of Contents
Version 1.1 rev Jan 2013
Page 64
iXon Ultra
, Features and Functionality
The third Keep Clean is the External Keep Clean Cycle. This cycle uses a different sequence of horizontal and vertical
clocking, as it must be able to respond to external events extremely rapidly but at the same time keep the Image area
of the sensor charge free. As can be seen from the gure below, the External Keep Clean Cycle consists of a continuous
cycle of one vertical shift, both Image and Storage, followed by one horizontal shift. When an external trigger is detected
the current cycle will complete before the exposure phase starts. It is worth noting that although the External Keep
Clean Cycle will complete the current cycle, this will not result in the total loss of signal during this time period, as only
one vertical shift will have occurred. For pulsed light of very short time duration, microseconds (i.e. of the order of one
vertical shift), the resultant image may appear to have shifted one row.
Figure 23: External Trigger Keep Clean Cycle