Samsung DVD-VR320/COM, Manual

Page: 248 / 249

Circuit Operating Descriptions
Samsung Electronics 14-49
14-15 OSD
The on screen display circuit consist of a character generator decoder, video mixer, sync separator and sync gener-
ator, sync detector circuit.
The data is decoded and generates characters in syncro with composite video signal applied pin 49, 50.
Also the sync detector circuit discriminates the presence of a video signal by detecting sync, if no sync is detected,
a blue screen is displayed. In other word, the OSD circuit displays character on the video when there is a video
signal or on blue screen when there is no video signal. (No sync).
49
CVin
4/2 fsc
oscilator
Sync signal
generator
H
Background
video signal
CVout
Blue Background
Super impose
IC601
Dot display
control
Character data
ROM
(128 characters)
Control circuits
(display position.
blinking. etc.)
registers
On-screen display
RAM
H/V
seperation
Display data
readout
control
AFC
V
Sync-tip
clamp
38
37
52
57
CVin2
47
50
C-Sync Slice
AFCC
AFCLPF
Fig. 14-32 Block Diagram