Panasonic TC-L42D2 Technical Manual page 38

Signal Process Circuit Explanation
The main function of the A board is to select and process one of the incoming video signals. Video inputs 1 and 2,
Component Video Input, HDMI inputs 1, 2 and 3, JPEG data from the SD card slot, and the composite video output of
the tuner are all connected to IC8001 for selection. The video input signal can be in any of the three formats: Video,
Y/C, YPbPr .
All analog signals that enter IC8001 undergo digital to analog conversion. When the signal source signal is composite,
a comb filter separates the video signal into Y and C (luminance and chrominance) signals. S-Video, which is already
Y/C separated, simply passes through the comb filter. The signal is then converted to RGB data.
At the completion of this process, the format of the composite or S-Video signal is now the same as a digital 480i
component signal. If the incoming video is in the 480p, 720P, 1080i, and 1080p format, the Y, Pb, and Pr signals
undergo A/D (analog to digital) conversion only.
Digital television reception of the tuner is output in the form of an IF (Intermediate Frequency) signal .
The transport stream from the tuner enters the VSB I/F (Interface) section of IC8001 where the video signal is
extracted and converted to RGB data. The output is provided to the Video Input I/F for selection. The JPEG data of
the SD card enters the JPEG I/F section of IC8001 for conversion into RGB data and output to the Video Input I/F
circuit. The video input interface outputs the selected picture data to the video process circuit.
The Video Process section of the IC performs all picture control operations such as brightness, contrast, color, tint, etc.
On Screen Display data such as channel numbers, Digital TV closed caption, and picture adjustments are mixed with
the video data. The RGB data is then converted to dual 14 bit LVDS (Low Voltage Differential Signaling) and output to
the LCD panel.
IC8001 handles all video applications. It serves as the controller that monitors all operations of the TV section of the
unit.
Slide # 38