Sony KP 48S70, Training Manual

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DTV Video Processing Block
Overview
This section will discuss how the DTV signals are processed. This in-
cludes video path V Chip/CC processing, sync path and signal format
detection.
The RA-4A chassis accepts two types of DTV inputs, component and RGB
with sync. There are three component inputs, Y, Pb (U) and Pr (V). The
sync is contained in the Y signal. There are five inputs for RGB. They are
R, G, B, HD and VD. The RGB and Y, Pb and Pr share the same jack.
The user must select which type of input they are using in the setup menu.
If the color appears wrong, ask the customer to make sure that menu
setting is the same type as the input.
Component Input Selected
If the DTV signal input is component video and Y, Pb, Pr is selected in the
setup menu, the set will work as follows. The Video inputs are sent di-
rectly to IC511 Video Processor. These signals are output from IC511
Video Processor back into itself and to IC1403 Main YUV Switch. The Y
signal is also sent to the internal Intelligent Sync Separator in IC511. It is
called intelligent because it determines which sync signal will be output
from it. If HD and VD from the DTV Sync inputs are detected, then they
are switched out to IC1008 Main CPU by default. If there is no VD or HD
input detected, but the Y input contains sync, then the sync will be sepa-
rated from the Y and output to IC1008 Main CPU. The Main CPU uses
the sync input to determine the format of the incoming signal.
If IC1008 Main CPU determines that a 480P or 1080I signal has been
input, the following occurs. The YUV signals that were input back into
IC511 are processed and output as RGB to the tubes. The H and V sync
from the Y signal is separated and output to the deflection circuits. The Y
signal input with U and V signals input to IC1403 Main YUV Select is
switched through to IC1303. IC1403 selects this signal because of the O
DTV input received from IC1008 Main CPU. The signal is passed by
IC1303 to IC1008 Main CPU. This signal is used for V Chip/CC. The
Main CPU also outputs the name of the format through its OSD lines so it
is displayed for the first few seconds after the input type is detected.
If a 480I signal is detected, the signal will not be directly output at IC511’s
RGB outputs. Instead it will follow the path through IC1403 to IC1307.
Here it joins the main video path and is output to the DRC circuit. How-
ever, its sync signals are output to the deflection circuits from IC511.
If the Main CPU detects a 720P signal, the following will occur. The screen
will dim and the words “This signal is not available” will be displayed.
IC511 Video Processor will not output the RGB to the tubes or the sync to
the deflection circuits. IC1008 Main CPU will output a command on the
I
2
C bus that will instruct the OSD CPU to output a Low on the O 720P line.
This line signals IC1307 to disable its DTV input and causes IC1303 to
select the input from the Y path shown.
RGB Inputs Selected
If the customer inputs RGB, HD and VD, and RGB is selected in the set
up menu, the video signals will be processed as explained previously.
The sync signals, which are input separately, are output from the Intelli-
gent Sync Separator instead of the sync from the Y so that IC1008 Main
CPU can determine what video format has been input.