Olympus OEP-3 - Page 126

4-18
OEP-3 V1 (UC)
4-2-3. Analog Video Signal Processing Block (Part of VPR-63 Board)
1. Input signal processing block (Decoder block)
(1) SYNC ON GREEN discriminator circuit
This board mounts a discriminator circuit that separates a sync signal from a green channel when no
sync signal is input at the time of an RGB signal input.
IC102 discriminates the existence of a sync input signal and controls a video switch (IC103) that
switches green input and sync input signals.
Fig. 1-1 SYNC ON GREEN Discriminator Circuit
D101
1SS123-T1
C121
0.1uF
R130
100k
R124
10k
R112
10k
Q102
2SC1623-T1-L5L6
C105
22uF
6.3V
C106
330pF
R122
47k
R115
22k
R116
2.2k
R119
2.2k
Q104
2SC1623-T1-L5L6
C122
0.001uF
R127
2.7k
(2/3)
IC102
MC74HC4538AFEL
(1/3)
IC102
MC74HC4538AFEL
C129
0.1uF
CL108
R136
1k
R135
1k
C124
22uF
6.3V
C126
22uF
6.3V
IC103
NJM2233BM
( TE2 )
3
2
1
15
C
14
CR
10
Q
9
Q
13
RD
12
11
1
C
2
CR
6
Q
7
Q
3
RD
4
5
2
CTL
3
IN2
7
OUT
1
IN1
8
GND
6
+V