cxa1812q Sony Electronics, cxa1812q Datasheet - Page 18

• Manufacturer Part Number: cxa1812q
• Description: S-terminal Compatible Video I/o
• Manufacturer: Sony Electronics

• Title Insertion Function (Timing Relationships)
• Relationship between Signal Flow and the Title Insertion function, and the Role of Pin 3
When VOW/VOW1 is high, the Y signal
replaces from the pedestal level to an
electric potential of 75IRE (white character);
when VOB/VOB1 is high, the Y signal
replaces from the pedestal level to an
electric potential of 10IRE (black character).
The C signal replaces to the chroma center
electric potential when VOW/VOW1 or
VOB/VOB1/CMUTE is high.
Because VOW/VOW1 have precedence,
VOW/VOW1 going high results in the
insertion of white character even if
VOB/VOB1 is high. If the settings are as
depicted in the diagram at right, white
character can be bordered with black.
Title insertion 2 is performed by a Y/C main
signal processing IC. Although no problem
arises in NTSC system, in the case of PAL
system, because it is necessary to connect a
color spectrum compensation IC with a delay
element between the Y/C main signal
processing IC and the CXA1812Q, if the title
is inserted in the Y/C main signal processing
IC, a temporal deviation occurs in the title
insertion position for Y and C. This problem
is resolved by using MUTE 3 in the C system
only. In addition, because a C signal
processed with MUTE 3 and with no
temporal deviation is output from Pin 3, the
composite video signal can be obtained by
mixing this signal with the Y signal.
Y output
C output
VF output
Y input
C input
<Positioning of the title insertion function within the overall flow of video signal processing>
CXA1812Q
MUTE 1
MUTE 3
MUTE 2
DDS 1
DDS 2
Pin 3
Title insertion 1
<Relationship between the title insertion position and the inserted signal>
Title insertion 3
Includes delay element
Y signal
VOW
VOW1
VOB
VOB1
CMUTE
C signal
Color spectrum
compensation IC
(required in PAL
system)
Composite (V) output
—18—
Title insertion 1
Title insertion 2
Title insertion 3
140 IRE
100 IRE
Y/C main signal processing IC
output
REC
75 IRE
O
X
X
MUTE
DDS
Title
insertion 2
Y, C, V
10 IRE
output
O
O
X
output
VF
O
O
O
REC
output
PB
input
CXA1812Q
Bolder
section