Service manual

CHAPTER 2
2 - 3 COPYRIGHT  2003 CANON INC. CANOSCAN 9900F REV.0 FEB. 2003 PRINTED IN JAPAN (IMPRIME AU JAPON)
2. Functions of Main PCB
1) Analog IC
Converts the image signals (analog signals) read by CCD into digital data.
- CDS (Correlated Double Sampling)
- AGC (Auto Gain Control)
- 8-bit A/D converter
2) ASIC
Performs the following transactions:
- DRAM control
- CCD timing clock creation
- Line buffer control
- CCD output line difference adjustment
- Image processing
- Shading correction
- Motor driver control
3) DRAM
Stores the shading compensation data when performing shading compensation.
Stores the image data when scanning.
4) Motor Driver
Supplies power to the drive motor.
5) USB Controller/ IEEE 1394 Controller
Controls data transfer between the host computer and ASIC.