LG 26LH1DC1-UB Service Manual page 36

3. Analog RF(NTSC) Video signal flow chart
RF Signal Input
The analog RF signal(NTSC) received in the input terminal of the tuner is converted to the base band signal in the
tuner(IC105) to send out the composite signal.
This CVBS signal is received by IC706 which is the analog video switch. The analog video switch receives the
CVBS signal sent from the tuner and the external signal, AV1, AV2, AV3, S-Video caption and Component caption
signal and sends out one of the signals.
The external input mode selected by the TV/AV button on the remote controller is the video signal selected for output.
The output signal is the decoded in the DTV controller of IC401 and converted to LVDS signal to be sent to the
LCD panel through the LVDS connector of P503.
Also the output signal from the analog video switch of IC706 is used as the caption signal.
This signal is amplified 2 times to send to the microprocessor(IC705), and IC705 arranges the caption signal to send
the caption information to the DTV controller through the I
Copyright©2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
(NTSC)
LCD Panel
*Tuner(NTSC) Video signal flowchart
IC105
TUNER
TU_CVBS
CVBS
IC706
for Caption
Analog MUX
(Video switch)
CVBS
IC401 I 2 C Comm.
DTV Controller
LVDS Signal
P503
LVDS Connector
2 C communications line.
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IC107
SD Video Filter
IC705
Micro Processor
LGE Internal Use Only