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Working principle analysis of the unit
Antenna reception signal RF will be sent to integrative tuner (contain HF and IF amplifier circuit), the
tuner is controlled by the command (SDA and SCL) of the MCU N801(M16C), select appropriate
channel to system switch, via HF amplifier and IF amplifier decode, output video signal CVBS and
second sound signal SIF.
CVBS, AV1, AV2, S-Video signal (Y signal of S-Video and AV1 video share the same channel) and
D-SUB signal via matched resistance, the signal separately through alone channel send to main IC
NS01 (SVP-WX68) video switch, A/D transition, digital decode, image scale and OSD superposition,
then send to LVDS level drive for LCD screen.
Video signal of YPbPr1, YPbPr2 via matched resistance to video switch NB05 (PI5V330), after
switch the select signal will be sent to main IC NS01 (SVP-WX68) video switch, A/D transition,
digital decode, image scale and OSD superposition, then send to LVDS level drive for LCD screen.
HDMI1, HDMI2, HDMI3 digital signal via digital video switch NA04(PS301), select one signal to
send to main IC NS01 (SVP-WX68) video and audio separate first, video signal via digital decode,
image scale and OSD superposition to output LVDS level drive for LCD screen; digital audio signal
I2S will be sent to N103 (SGTV58xy audio process and volume control).
Audio signal of AV1, AV2(AV1 and S-Video share the same audio channel), YPbPr1, YPbPr2.
D-SUB/DVI HDMI and SIF signal will be sent to audio processor N103 (SGTV58xy) sound switch,
the select signal output through three ways. One way via volume, treble and bass control, sound
effect processing, then separate to left and right channel and send to sound amplifier NA01,
NA02(TPA3001D1) amplifying, then send to speaker; one way also separate to left and right
channel and send to earphone amplifier N104 (NJW1109) volume control and amplify, then send to
earphone socket; the other way send to AV OUT.
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