Ricoh PRIPORT VT 2000 Series Service Manual page 49

28 February '91
2.5.3 Shading Distortion Correction:
Amp
PKHTM
Peak
Hold
Circuit
L. SYNC CN403-29
(
Since the output of the CCD varies according to both the CCD and the
intensity of the fluorescent lamp, shading distortion is corrected electrically
as well as mechanically (shading plate).
SW2 SHMRT
VPH
53%
VT2100/2130/2150: 1.7V
VT2300/VT2500:
(CN403-31)
Read CN403-25
(CN403-27)
Write CN403-27
(CN403-29)
SHMRT
PKHST
PKHTM
BLSET
): VT2300/VT2500
Pixels Data
B
VH
1 X
A/D
Converter
1 Y
VL
Current/
D/A
Voltage
Converter
Convertor
VR(+)
5 lines
Shading Distortion Memory
2-22
4 bit Signal
4 bit Signal
VR(-)
1.4V
1.7V: VT2100/2130/2150
1.4V: VT2300/VT2500
Shading
Distortion
Memory