Panasonic DX-600 Service Manual page 216

0V
OS
DOS
Shading Correction Circuit
The Shading Correction Circuit, included in IC30, is provided to correct for reduction in LED lamp
intensity around the optical lens and LED lamp intensity distortion due to shading of each bit. This circuit
scans the white reference on the transmitting document plate immediately before the document reaches
the scanning position and writes a compensation value according to the distortion of the waveform, at
the time, into the S-RAM (IC31).When the actual picture signal is input, the circuit corrects the picture
signal shading, according to this compensation value. This shading is carried out for each page during
transmission or copy.
Offset Control Circuit
The Offset Control Circuit consists of Q15, Q13, IC30 and IC28, and controls the black level of the CCD
output to be at 0V by using the input.
Picture Signal Binary Coding Correction Circuit
The Picture Signal Binary Coding Correction Circuit is included in IC30. It is used to obtain a binary
coding signal which is a corrected picture and error diffused signal of a false halftone signal, which is
detected from a shaded picture signal.
Edition 1.0
CCD Output
IC28, 2
+5V
Q15
Q13
-5V
3V
0V
IC28, 1
R288
C175
R285
216
ABC Circuit Output
32
IC30
37
19
41
39
Control
Circuit
40
DX-600/800
APR 2002