Samsung SV-DVD50 Training Manual page 114

7-9 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 19.
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).
2
2fsc
4 fsc
oscilator
21
CVin
Sync-tip
clamp
6
7
H
Sync signal
V
generator
Super impose
Dot display
control
Charater data
(128 charaters)
Display data
readout
control
Control circuits
(display position.
On-screen display
blinking. etc.)
registers
Fig. 7-35 Block Diagram
Background
video signal
Blue Background
ROM
RAM
H/V
seperation
Circuit Operating Descriptions
19
CVout
24
C-Sync Slice CVin2
7-39