4-23
OEP-3 V1 (UC)
2. Output Signal Processing Block (Encoder Block)
(1) Video encoder block
On this board, BH7243KV (IC407)(made by ROHM) is used as the encoder of a video signal. This
circuit incorporates an eight-bit, three-channel DA converter and video encoder. By inputting a
subcarrier and composite sync signal, an eight-bit RGB digital signal can be converted into a
composite video signal by one chip. The output of RGB, S video, and composite video signals can be
driven in 75 ohms. Moreover, this circuit has an internal OSD (On Screen Display) selector switch.
Setting and adjustment are all performed by I
2
CBUS. An OSD character signal is sent from the SY-
282 board.
Fig. 1-7 Video Encoder Circuit
GND
TP403
L404
C434
0.1uF
C435
100uF
6.3V
L402
0.1uF
C410
C411
47uF
6.3V
C432
0.1uF
C431
47uF
6.3V
C429
0.1uF
C428
0.1uF
C426
0.1uF
C425
0.1uF
C422
0.1uF
C421
0.1uF
R416
33
CL404
R417
33
R418 33
C419
0.1uF
IC407
BH7243KV
49
BDATA3
50
BDATA2
51
BDATA1
52
BDATA0
53
DACOFF
54
DGND
55
BDACOUT
56
GDACOUT
57
RDACOUT
58
AVCC1
59
RIN
60
OSDR
61
GIN
62
OSDG
63
BIN
48
BDATA4
47
BDATA5
46
BDATA6
45
BDATA7
44
GDATA0
43
GDATA1
42
GDATA2
41
GDATA3
40
GDATA4
39
GDATA5
38
GDATA6
37
GDATA7
36
RDATA0
35
RDATA1
34
RDATA2
32
DVDD
31
VCLK
30
RDATA4
29
RDATA5
28
RDATA6
27
RDATA7
26
OSDCLK
25
SDA
24
SCL
23
VREG
22
AGND1
21
SCIN
20
CSYNCIN
19
SYNIN
18
NT/PAL
16
SYNCOUT
15
BFPOUT
14
YTRAP
13
VOUT
12
TEST
11
COUT
10
YOUT
9
AVCC2
8
AGND2
7
BOUT
6
GOUT
5
ROUT
4
NC2
3
NC1
2
OSDOFF
64
OSDB
33
RDATA3
17
NC3
1
OSDSW
RDA7
RDA6
RDA5
RDA4
RDA3
RDA2
RDA1
RDA0
BDA7
BDA6
BDA5
BDA4
BDA3
BDA2
BDA1
BDA0
GDA7
GDA6
GDA5
GDA4
GDA3
GDA2
GDA1
GDA0
BDA7-0
BDA7-0
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