Canon FAX L1000 Service Manual page 213

a-4) DRAM (IC 3, 31)
This 16-Mbit DRAM is backed up by rechargeable battery (approx. 12 hour after AC
power interruption), and is used as memory for storing image data and MPU work area.
a-5) SRAM (IC 5, 6)
These 256-kbit SRAMs are backed up by lithium battery. SRAM holds data registered for
system control and communications management information.
a-6) RTC (Real Time Clock) IC (IC 7)
A Seiko epson RTC-63421A is used as the RTC. The RTC IC is backed up by lithium
battery, and counts the date and time.
b) Document scanning section (SCNT board)
The document scanning section consists of the following components and processes
scanning image data.
b-1) Image processing IC (IC 20)
The main functions of the image processing IC (UHQ-6.6) are as follows:
•A/D conversion
•Input signals from the contact sensor are A/D converted
•ABC (Auto Background Control)
•AGC (Auto Gain Control)
•Read density - document density conversion
•Edge enhancement processing
•Binarization processing
•Notch eliminate processing
•Autohalftone processing
•Error diffusion processing
•Parallel/Serial conversion
•Dark correction
•Adjust variations in the output of transistor array chips when the LED is turned off
•Shading correction
•Contact sensor interface
•SRAM interface
FAX-L1000 Chapter 3: Technical Reference
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