LG 15LW1R, Руководство по обслуживанию

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DESCRIPTION OF BLOCK DIAGRAM (Wireless TV TX)
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1. CPU & Memory Block
S3C2800 Samsung CPU is used for the main processor. S3C2800 offers embedded PCI Host Bridge. Input frequency is
6MHz and maximum output frequency is 200MHz. PCI interface supports 32bit data bus at 33MHz/66MHz and wireless TV
TX system is using 33MHz system. Wireless TV TX system supports 4Mbytes Flash Memory and 32Mbytes SDRAM
Memory. Flash Memory is MX29LV320ABTC-90 and SDRAM Memory is composed of two 16 Mbytes SDRAM
K4S281632F-TC75.
2. MPEG Encoder
MPEG II A/V Encoding system is used by Conexant CX23416-12(U502). It contains memory controller and interfaces
directly with HY57V643220DT-7(U501). CX23416 is interfaced with CPU by PCI interface. Input Analog signal is converted
to digital signal and Mpeg encoded by CX23416 and transmitted to wireless TV RX system by wireless interface. It supports
ITU-T 656 format and input frequency is 27MHz.
3. Video/Audio Processor & Micom
VCT4973(U603) contains several functions which is essential for wireless TV TX system. VCT4973(Micronas inc) contains
Video processor, Audio processor, micom function, V-Chip function, I2C interface. Input crystal oscillator frequency is
20.25MHz. Video/Audio signal form external AV interface is transferred to A/D Converter. Power Management function is
performed by micom function. When Adapter is connected with wireless TV TX system, Standby power 1.8V, 3.3V is applied
to the system and maintains Standby status and if you push the power switch, Normal power is applied to the system.
4. Wireless LAN
Wireless LAN card is LG INNOTEK inc Wireless LAN card(Model:LWMM-3002A). Wireless LAN interface is interfaced by
MiniPCI Type IIIA interface which is Soft MAC. Main chip is Conexant Inc. wireless LAN chip. Wireless LAN card is
convertible with 802.11b(max 11Mbps) & 802.11g(max 54Mbps).
5. TV Tuner
TV Tuner is LG INNOTEK Inc. TAEW-G351P. SAW Filter is not included to the tuner and internal booster is included to the
tuner. The tuner adopts external 2 Antenna Connectors. One is for input TV signal and the other is output TV signal. TV
tuner is controlled by VCT4973 through IIC interface. SAW Filter is EPOS Inc. X6966. X6966(U802) uses 38.9MHz IF
frequency. IF signal from TV Tuner is passing through SAW Filter and transferred to VCT4973. TV Tuner’s 33V is made by
Transistor, Diode circuit and PWM signal. VCT4973 is sending PWM signal to 33V circuit.
6. AD Converter
This circuit uses Mstar Semiconductor Inc. MST9883(U702) as Video ADC. In case of Audio ADC, TI Inc. PCM1802 is
used. Video signal from VCT4973 is transformed to ITU-T R.656 format and transferred to MPEG Encoder. Audio signal
from VCT4973 is transferred to Audio ADC PCM1802(U701) and passed to MPEG Encoder. PCM1802 gets input frequency
12.28MHz. MST9883 and PCM1802 has IIC interface and VCT4973 controls them through IIC interface.
7. Clock distribution & Spread Spectrum
Clock system is mainly composed of CDCVF2505 and CY25812. Clock system offers 33MHz frequency to main CPU PCI
master/slave system, MPEG Encoder, and Wireless LAN(MiniPCI circuit). Input Crystal frequency is 16.6MHz and this
frequency is applied to CDCVF2505 and it outputs 33MHz. 33MHz can interfere with other signals and be EMI main source
signal. Cypress Inc. CY25812 is used to spread frequency around 33MHz and reduces EMI value to adequate level. .
8. DC-DC Converter
DC-DC Converter is composed of LTC1628 and regulator circuits. 110V/220V 60Hz DC power adapter output signal is 16V
and wireless TV TX system input power is 16 V. 16V input power is converted to 8V by regulator (78M08), and to standby
5V, 3.3V by regulator (LTC1628) and Normal 5V, 3.3V is controlled by the signal ON/OFF from VCT4973. From standby
3.3V, standby and Normal 1.8V, 1.25V is made by regulator (FAN1117, REG1117). 1.8V power is used by VCT4973, and
main processor S3C2800. 1.25V is used by MPEG Encoder.
Also, 5V, 3.3V Power control is done by FET circuit controlled by micom in A/V multi processor VCT4973. Once external
Power TACT switch signal is detected by micom in VCT4973, micom remembers its signal status as toggle method. Push
the button and power is on. If you push again, power is off. This way power is controlled. If DC adapter is connected,
Standby power(5V, 3.3V, 1.8V) for TV tuner and video/audio system is maintained without regard to power switch push
status.
In case of TV Tuner(TAEW series). 5V and 33V is needed., PWM signal from VCT4973 is amplified by transistor and
rectified by diode. This way 33V is made. This 33V is also standby power. In Standby status, TV Tuner input/output is
operating.