XOCECO LC-27W18S, Руководство по обслуживанию

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Working principle analysis of the unit
1. Analog signal flow
Antenna reception signal send to integrative tuner (contain HF and IF amplifier circuit), the tuner is
controlled the command (SDA and SCL) of the MCU N301 (M16C), select appropriate channel to
system switch, via HF amplifier and IF amplifier decode, output video signal of 2VPP and sound
signal of 1VPP.
Sound signal (SCART1, 2 sound, AV sound, YPbPr, HDMI and D-SUB) via N581 HEF4052BT
(sound diverter switch) to output signal, it send to N801(MPS3410 sound processing and volume
control) switch of audio. Select right/left sound channel, their send to digital sound amplifier N803
(TPA3008) amplify, then send to speaker.
After output video signal of tuner, SCART1 video signal and RGB signal via matched resistance, the
signal thought alone channel send to main decode IC(N101 SVP-EX52) video switch, A/D
transition, digital decode, image scale and OSD superposition, then send to LVDS level drive for
LCD screen.
AV, S-Video, SCART2 video and Y/C signal thought matched resistance, the signal send to the
N506 video switch (SN74CBT3257CDR), via switching to selected signal (EX52_Y and EX52_C) to
main decode IC (N101 SVP-EX52) video switch, A/D transition, digital decode, image scale and
OSD superposition, then send to LVDS level drive for LCD screen.
D-sub and YPbPr signal thought matched resistance, the signal send to the N507 video switch
(SN74CBT3257CDR), via switching to selected signal (EX52_YUV) to main decode IC (N101
SVP-EX52) video switch, A/D transition, digital decode, image scale and OSD superposition, then
send to LVDS level drive for LCD screen.
2. Digital signal flow:
HDMI signal thought HDMI reception chip N405 (SiI9011HDMI with HDCP function), after receive,
output digital format signal send to SVP-EX52 PIP channel thought image scale and OSD
superposition, then send to LVDS level drive for LCD screen. The HDMI chip output audio digital
format signal change to analog sound signal from N403 (CS4344 audio DA transfer chip), then
N581 switched to N801 (MPS3410 sound processing and volume control).
3. TELETEXT function
This unit adopt main decode IC N101(SVP-EX52) of Trident company, it has TELETEXT decode
function, after decoded, the teletext information in OSD display.