Ricoh B245-62 Service Training page 28

SBU (Sensor Board Unit)
The CCD converts the light reflected from the original into an analog signal.
Each CCD line has 7,400 pixels, producing a resolution of 600 dpi (23.6
lines/mm).
SBU does analog processing and analog to digital conversion.
See the notes for more details.
Slide 28
The CCD converts the light reflected from the original into an analog signal. The CCD
line has 7,400 pixels and the resolution is 600 dpi (23.6 lines/mm).
The CCD has two output lines, for odd and even pixels, to the analog processing circuit.
The analog processing circuit performs the following operations on the signals from the
CCD:
1. Z/C (Zero Clamp):
Adjusts the black level reference for even pixels to match the odd pixels.
2. Signal Amplification:
The analog signal is amplified by operational amplifiers.
After the above processing, the analog signals are converted to 8-bit signals by the A/D
converter. Each pixel will be assigned a value on a scale of 256 grades. Then, the
digitized image data goes to the BICU board.
For more details about analog signal processing and A/D conversion, refer to the core
technology manual.
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B245-62 / PD-C4