Working Principle Analysis Of The Unit - Sanyo LCD-22XR7S Service Manual

Working principle analysis of the unit

The RF signal received by antenna will be sent to tuner TUNER1, then IF signal will be
obtained through high amplifier and mixed frequency, through pre-intermediate amplified by V15,
then it will be sent to acoustic surface-wave Z17 to do IF filter and get better IF characteristics, then
it will be sent to N3 (TDA4470) to do intermediate amplification, phase-locked loop VCO and
synchronous wave detection to get video signal TV-V; after pre-intermediate amplification IF will
also be sent to acoustic surface-wave Z16 to do filter at the same time, then it will be sent to
TDA4470 to do intermediate amplification and output the second sound intermediate frequency
signal TV-SIF.
The TV-V signal output from TDA4470 together with TV-SIF will be sent to main IC
NS2(MST9E19B).
Video signals of VGA and HDMI will be sent to MST9E19B, too.
Video signal of YPbPr and Video RGB of SCART1 via video switch N5(PI5V330) will be sent to
MST9E19B.
Video signal V (CVBS) of SCART1, YPbPr L/R and SCART1 L/R will be sent to MST9E19B.
The main IC NS2(MST9E19B) is a high performance and fully integrated IC, which can realize
video demodulating, video switch selection, A/D and D/A conversion, interlace/de-interlace
processing, modes conversion, OSD and low-voltage differential output, etc. And it also has
functions of audio demodulation, selection, processing and MCU.
The video signal via MST9E19B processing, output 4 pairs differential signal and 1 pair clock
signal for LCD panel display. TV-V output from TDA4470 via double video amplifying, it will be sent
to SCART1 for AV-OUT.
Audio signal via MST9E19B processing will be sent to sound amplifier NV1 (TDA7266SA)
amplifying to speaker. TV-SIF via MST9E19B demodulating and sound processing then output to
LM358D amplifying, the signal will be sent to SCART1 as AV-OUT.
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