69
28. Grand Wega Video Process
FIGURE 28-4 - TWIN PICTURE MODE, ANALOG INPUTS
Sub pix
IC3011
Main pix
IC3006
Main pix
from
IC3006 &
DRC
S
Main pix
from
IC3006 &
DRC
S
a
b
c
FIGURE 28-3 - VARIOUS TWN PICTURE DISPLAYS WITH NTSC AND/OR HIGH
DEFINITION (HD) SIGNALS. (HD INPUT FROM VIDEO 5 OR 6)
Main/
DRC
HD
Left = High Definition
(480p, 720p, 1080i) &
Right = NTSC (480i)
Main/
DRC
Sub
pix
Two NTSC (480i)
pictures displayed
Two 480i (NTSC) Pictures Input
Refer to Figure 28-4, which indicates where the larger picture’s signal comes from. When either both pictures
are the same size (Figure 28-4a) OR if the LEFT picture is the larger picture (Figure 28-4b), the DRC circuit (BB
board) is used to improve the quality of the 480i (NTSC) signal. The main picture from IC3006 (BC board) is
positioned on the LEFT side (by the MID circuit on the BB board).
When the picture on the LEFT becomes the larger (Figure 28-4c), the Main and Sub input signals switch (BC
board) and the MID process (IC509, BB board) also switches the picture position. This double signal crossing
allows the channels to be at the same place on the screen (but the signal paths are different). This switching is
done to ensure the high-quality DRC signal is employed by the larger picture.
As the user increases the picture size from smaller to larger, a slight delay occurs when the right picture just
begins to enlarge. This allows both the SEL switch ICs (BC board) and the MID circuit (BB board) to switch
positions. The picture freezes for a moment until both switches have been made, and then the picture frame
continues to increase in size.
One 480i (NTSC) Picture Input and
One HD (480p/720p/1080i) Picture Input
When one twin view picture contains a HD signal, that HD picture always takes the SUB signal lower path (Figure
28-1) into the MID IC509 and appears on the LEFT side of the screen.
