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3. I/O Options

Figure 4 shows the four major I/O options available :

• video input and output
• audio input and output

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The digital RF signal(ATSC/QAM) received in the input terminal of the tuner is converted to the base band signal in
the tuner(IC105) to send out 8 bit transport stream.
This signal is transferred to the FPGA chip of IC901. FPGA chip decrypts the TS data so that it can be decoded by
the DTV decoder in the next terminal.
The TS data decrypted by IC901 is decoded by the video decoder of DTV controller of IC401 and converted to the
LVDS signal.
The LVDS signal is transferred to the LCD panel through the P503 connector to be displayed on the LCD panel.

RF Signal Input

(ATSC/QAM)

LCD Panel

Unscrambled
TS Data

TS Data

LVDS Signal

IC105

TUNER

IC901

ALTERA FPGA

IC401

DTV Controller

P503

LVDS Connector

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RF Signal Input

(ATSC/QAM)

I

2

S

TS Data

Unscrambled
TS Data

IEC958

IC401

DTV Controller

IC901

ALTERA FPGA

Speaker

Stereo(L/R)

IC708

Digital Audio Amp.

P501

SPDIF Output

Connector

P706, P707

Audio Output

Connector

IC105

TUNER

The digital RF signal(ATSC/QAM) received in the input terminal of the tuner is converted to the base band signal in
the tuner(IC105) to send out 8 bit transport stream.
This signal includes both the video and audio signal. The audio received by the DTV controller through IC901 is
decoded for Dolby AC3 in the audio decoder and the PCM data is transferred in I

2

S format.

This signal is converted to stereo signal(L/R) from the digital audio amp(IC708) and then sent to the internal speaker
through audio output connector(P706, P707).
Also for the digital audio data in IC401, the PCM or AC3 compressed data by user setting is sent out in SPDIF
format through P501.

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RF Signal Input

(NTSC)

LCD Panel

CVBS

CVBS
for Caption

I

2

C Comm.

TU_CVBS

LVDS Signal

IC105

TUNER

IC706

Analog MUX

(Video switch)

IC401

DTV Controller

IC107

SD Video Filter

IC705

Micro Processor

P503

LVDS Connector

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

2

C communications line.