JAI TM/TMC-4200CL 사용자 설명서

In Pulse Width Control (PWC) Mode, the exposure time is controlled by the external trigger. When an 
external trigger is applied, one discharge signal (Vsub) is generated right after the active edge of the 
trigger. The exposure starts when  the discharge signal is in the off state. The exposure is off following 
the trigger active off. Exposure time is controlled by the pulse width of the external trigger. Because the 
CCD requires some overhead from trigger active off to the transfer gate event, the actual exposure time 
is equal to:

Exposure Time = Pulse Width +20.6

μs

Since one discharge signal (Vsub) is generated right after the active edge of the trigger, it is 
asynchronous with LDV, and the discharge signal may happen during an active video transfer period, 
visible reset noise may show in the current image. To avoid reset noise, the maximum trigger frequency 
in PWC mode should be less than 1/ (exposure time + one frame transferring time). 

The minimum active period of the external trigger is 5

μs. Theoretically, the maximum active period of 

the external trigger is unlimited.

 

But, since images obtained at 25

o

C are often very degraded due to 

thermal noise, it is recommended the active period of the external trigger be no longer than one second.