Sbu Block Diagram - Gestetner G060 Service Manual

6.2.2 SBU BLOCK DIAGRAM

O R(B)
Analog Amplifier
E
A/D Converter
O G
Analog Amplifier
C C D
E
A/D Converter
O B(R)
Analog Amplifier
E
A/D Converter
SBU
Signal Processing
1. Signal Amplification
• Odd-pixel and even-pixel RGB analog signals from the CCD are amplified by
operational amplifiers.
2. Signal Composition
• The amplified signals (even-pixel and odd-pixel for each RGB color) are
combined by the MPX circuit after A/D conversion.
A/D Conversion
• The analog signals (CCD output) are converted to 10-bit (1024 gradations) digital
signals.
White Level Correction:
• White reference plate scanned before the original.
• Data is updated before each scan.
• Corrects for variations in the white level across the page, including irregularities
in the CCD and the optics across the main scan.
Others
The SBU controller exchanges the R and B signals if the original is scanned by
using ARDF.
SM
10 bit R 10 bit
G 10 bit
10 bit S B U
Controller
10 bit B 10 bit
E E P R O M
6-7
IMAGE PROCESSING
Field 8 bit
M e m o r y
Field
8 bit
A S I C
M e m o r y
8 bit
IPU
G570D901.WMF
G570