Pulse Width Control Trigger Mode - JAI CV-M77 Operation Manual

time (accumulation time) is governed by the fixed shutter speed set up by the rear panel DIP-
switches or via RS-232C control. The resulting video signal will start to be read out after the
selected shutter time. The WEN pulse indicates the start of valid video signal. Refer to timing
charts for details. A new trigger pulse must not be applied before the video read out has finished. If
the camera is synchronized to an external HD signal, there are some requirements to the phase
between the ext. HD and the Ext. trigger. The falling edge of the trigger should be less than 8 sec
before the falling edge of the ext. HD and less than 2 sec after the falling edge of the ext. HD (see
figure 6-2). Otherwise the jitter will be too high.
To use this mode:
Set SW1-5,6 and to SW1-7 on the rear plate of the camera to "OFF" or use the RS 232C control.
CV-M77 Input Signal Phase Relation
Phase Relation of TRIG and EXTHD
TRIG
EXTHD
Phase Relation of EXTVD and EXTHD
EXTVD
EXTHD
6.3.2

Pulse Width Control Trigger Mode

This trigger mode where the length of the trigger pulse determines the exposure time operates in H
non-reset mode. In H non-reset mode the trigger pulse and the HD signal are synchronized. The
exposure will start at the first HD pulse after the falling edge of the external trigger signal. The
exposure ends at the rising edge of the external trigger signal. The trigger pulse must be longer
than >1H (51 sec) and shorter than 2000 H. To avoid jitter the camera should be synchronized to
an external HD. There are some requirements to the phase between the ext. HD and the Ext.
trigger. The falling edge of the trigger should appear in the interval less than 8 sec before the
falling edge of the ext. HD and less than 2 sec after the falling edge of the ext. HD and the rising
edge off the trigger should be fall in the interval 8 sec before the rising edge of the ext. HD and 2
sec after rising edge of the ext. HD. (See figure 6-2).
The resulting video signal will start to be read out after the rising edge of the external trigger signal.
The WEN pulse indicates the start of valid video signal. Refer to timing charts for details.
A new trigger pulse must not be applied before the video read out has finished.
To use this mode:
CV-M77
A B
A=Less than 8 s
B=Less than 2 s
B=Less than 42 s
Figure 6-2: Input signal phase relation
- 11 -
A B
B C
C=More than 0.5 s