STC-A33A
User Guide
18
Rev 1.0
B. Pulse Width Trigger Mode
In the “Pulse Width Trigger Mode” with positive polarity, the camera exposure starts at the rising edge of the trigger signal and
stops at the falling edge of the trigger signal. Therefore, in the case that the exposure positive polarity is selected, the actual
exposure occurs when the trigger signal is at its high state.
1. Pulse Width Trigger Mode (V-Reset)
Note 1: The camera does NOT switch to normal mode when the long exposure mode is selected. The timing chart above
shows when the long exposure mode is selected.
Note 2: The internal VD signal is reset immediately after the exposure is finished as depicted above; the video
output signal is sent out according to that reset VD timing.
Note 3: The exposure time is controlled by the pulse width of the trigger signal.
Note 4: External VD signal input is continuous during the external sync mode and it is disregarded during the trigger
mode.
Note 5: The WEN signal does not output when the exposure by the trigger signal does not exist.
N o r m a l m o d e
Exposure time
M a x . 1 H
Trigger mode
N o r m a l m o d e
N o t e 1
: A u t o m a t i c a l l y s w i t c h e s
t o n o r m a l m o d e i f t h e p u l s e
w i d t h o f t h e t r i g g e r s i g n a l i s
m o r e t h a n 5 0 0 m s e c .
Function mode
Internal VD
CCD exposure
Trigger signal
(Positive)
Video out
N o t e 3
WEN signal out
N o t e 5
N o t e 4
N o t e 2
