CXD2408R View Datasheet(PDF) - Sony Semiconductor

Part Name

Description

Manufacturer

CXD2408R

Timing Generator for Progressive Scan CCD Image Sensor

Sony Semiconductor 

CXD2408R

4. Random Trigger Shutter

The random trigger shutter is different from the conventional electronic shutter in that the exposure beginning

can be freely set. The exposure period (shutter speed) can be set as with the conventional electronic shutter.

In this mode, XSUB rises for each 1H, and the charge stored in the sensor is discharged. Because the V clock

(XV1 to XV3) is continuously operating, any unneeded charge in the vertical CCD is eliminated.

XSG pulse is stopped until the external trigger is detected. The image cannot be monitored until the external

trigger is detected and the signal is read out.

When an external trigger is input in this state, HD is forcibly reset when the trigger falls, and XSUB falls once to

clear the charge and then halts. XV1 to XV3, XCPDM, XCPOB, and PBLK are reset with HD. From this point,

exposure begins, and after the preset exposure period has passed, the XSG pulse falls, the charge is

transferred from the sensor to the vertical CCD, and exposure ends. The XSG pulse falls with the time set as

in conventional electronic shutters, regardless of VD. Because HD is reset, the exposure period is accurate in

1H units. The WEN pulse is generated synchronously with the XSG pulse. As the WEN pulse specifies the

signal start, it can be used as the sync signal for writing image data into the frame memory.

In the random trigger shutter mode, V-direction functions of a sync signal generator are halted. As a result,

sync signals VD and FLD are also halted.

TRIG

HD

XSG

XSUB

XV1

XV2

XV3

WEN

HD reset

XSUB reset

Shutter speed

– 15 –

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