Circuit Descriptions
7.
7.
Circuit Descriptions
Index of this chapter:
7.1 Introduction
7.2 Front-End
7.3 “Zinwell” digital bolt-on module
Notes:
•
Only
new
circuits (circuits that are not published recently)
are described.
•
Figures can deviate slightly from the actual situation, due
to different set executions.
•
For a good understanding of the following circuit
descriptions, please use chapter
and
10. Circuit Diagrams and PWB Layouts
. Where necessary,
you will find a separate drawing for clarification.
7.1
Introduction
The LC9.2A LA chassis is a digital derivative from the LC9.1A
LA chassis. It has an additional “Zinwell” module for digital
reception. Only this module is depicted in this manual. For all
other circuitry, refer to the LC9.1A LA Service Manual.
7.2
Front-End
Key components for the analogue tuner section (AP region)
are:
•
UV1856L analog tuner with splitter
•
K7257 video SAW filter
•
K9362 audio SAW filter
•
TDA9886T analogue IF demodulator.
For trouble shooting info, refer to paragraph 5.6.6 Trouble
Shooting Tuner section.
The analogue tuner routes an analogue signal directly to the IF
demodulator (via the SAW filters), whereas a digital signal is
passed to the Zinwell digital bolt-on module via the splitter. The
output signal from this module is fed back to the SSB via a
HDMI connection.
7.3
“Zinwell” digital bolt-on module
This chassis is equipped with the digital “Zinwell” bolt-on
module with the TD1318AF digital tuner, for digital reception. It
has the following specifications:
General:
•
12 V supply
•
RF input: RF DTMB multi-carrier signal input
•
Digital output: HDMI
•
Analogue output: CVBS and Audio L/R
•
Control: UART and Reset
•
Service: UART port
•
Others: USB software update.
Tuner:
•
TD1318AF
•
Input frequency: 47 - 862 MHz
•
IF frequency: 36.0 MHz
•
Channel bandwidth: 8 MHz
Demodulator:
•
LGS-8913-A1 (Legend Silicon)
•
Constellation: 64-QAM, 16-QAM, 4-QAM
•
Guard interval: PN945 (1/4)
•
Code Rate: 0.4, 0.6
•
De-interleaving: M = 720
Video
•
Decoding: MPEG2 (including MPEG still-picture decoding)
•
Output format: HDMI (1080i), CVBS
Audio
•
Decoding: MPEG1 Layer I/II, MPEG2 Layer I/II, Dolby
Digital
•
Output format: HDMI, analogue stereo 2-channel
Figure 7-1 Digital bolt-on module system connection
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