Lexmark 3200 Service Manual page 17

2. CCD signal processing circuit
R
CCD MUX
G
B
The video noise suppression circuit is to eliminate the reset noise and low frequency noise of
CCD and then PGA performs video gain control. The "level shift" circuit is used to bias the
PGA output to satisfy the reference bottom requirement of the A/D converter. The "DC-
OFFSET Adjust" circuit is used to adjust the bias level of video signal.
* PGA: Programmable gain amplifier
Video Noise
Suppression PGA*
Circuit
DC Offset
Adjust Circuit
1-13
A/D
Level
Shift Converter