Working Principle Analysis Of The Unit - Sanyo LCD-DP55441 Service Manual

3. Working principle analysis of the unit

1. NTSC/ATSC signal flow:
Antenna reception NTSC/ATSC signal will be send to tuner U32, t h e n T u n e r w i l l b e
demodulating and output differential IF+ IF- signal .
These differential IF+ IF- signal will send to the master control IC U1 to video/MPEGII decode, de-
interlace and scaler, then output LVDS level drive for panel display.
The differential signals will be fed into U1 to demodulate audio signals , after demodulating, pre-
amplifying, bass adjusting and volume control, the sound signal will b e t r a n s f o r m i n t o d i g i t a l
I 2 S s i g n a l b y scaler I C and sent to digital amplifier U5 amplifying, then output to speaker.
2. AV VIDEO signal flow
Video path AV signal switch by menu "Inpput list" via terminal socket, the signal and the Video1
path AV signal will be fed to U1 to perform video decode, de-interlace and scaler, then output LVDS
drive level for panel display.
Audio signal from AV terminal via matched resistance is fed to U1 to bass adjust and volume control,
the sound signal will be transfered into digital I2S signal by scaler IC and sent to digital amplifier U5
amplifying, output to speaker.
3. PC/YPrPb signal flow
PC and the Video2 and Video3 path YPbPr signal are via terminal sent to U1 A/D conversion,
output R/G/B of 24 bit to back end module to digital decode, image scale, then send to LVDS
level drive for panel display.
Sound signal of PC/YPrPb t e r m i n a l via matched resistance a n d sent to U1 to bass adjust and
volume control, the sound signal will be transform into digital I2S signal by scaler IC and sent to digital
amplifier U5 amplifying, then output to speaker.
4. HDMI signal flow
HDMI video signal via terminal sent to U1 to digital decode, image scale, then output LVDS drive
level for panel display. HDMI audio signal via decoder built-in terminal sent to U1 is fed to back end
to bass adjust and volume control, the sound signal will b e transform into digital I2S signal by
scaler IC and sent to digital amplifier U5 amplifying, then output to speaker.
5. MEDIA signal flow
The JPEG file via USB terminal send to U1 to MPEG decode , image scale , then output LVDS
drive level for panel display .
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