Service manual

CHAPTER 2
2 - 3
COPYRIGHT © 2001 CANON INC. CANOSCAN D1230U/D2400U REV.0 MAR. 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
2. Functions of the Main PCB
1) Analog IC
Converts the image signals (analog signals) read by the CCD into digital data.
- CDS (Correlated Double Sampling)
- AGC (Auto Gain Control)
- 16-bit A/D converter (Analog-to-Digital Converter)
2) ASIC
Performs various processings:
- DRAM control
- CCD timing clock creation
- Line buffer control
- CCD output line difference adjustment
- Image processing (Binary processing, Image inversion)
- Shading correction
- Motor driver control
3) DRAM
Stores the shading correction data when performing shading correction, and the image data
when scanning.
4) Motor Driver
Supplies power to the drive motor.
5) USB Controller
Controls data transfer between the host computer and ASIC.