LG L602i, Service Manual

Page: 36 / 192

3. TECHNICAL BRIEF
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3.8. Subsystem(MSM6250A)
3.8.1. ARM Microprocessor Subsystem
The MSM6250A device uses an embedded ARM926EJ-S microprocessor. This microprocessor,
through the system software, controls most of the functionality for the MSM, including control of the
external peripherals such as the keypad, LCD, RAM, and ROM devices. Through a QUALCOMM
proprietary serial bus interface (SBI) the ARM926EJ-S configures and controls the functionality of the
RTR6250, RFR6200, RFL6200, and PM6650-2 devices.
3.8.2. UMTS Subsystem
The UMTS Subsystem performs the digital UMTS signal processing. Its components include:
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Searcher engine
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Demodulating fingers
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Combining block
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Frame deinterleaver
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Viterbi decoder
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Up-link subsystem
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Turbo decoder
On the down-link channel the UMTS subsystem searches, demodulates, and decodes incoming
CPICH, CCPCH, SCH, and Traffic Channel information. It extracts packet data from the downlink
traffic channel and prepares the packet data for processing. For the up-link, the CDMA subsystem
processes the packet data and modulates the up-link traffic channel (DCH).
3.8.3. GSM Subsystem
The GSM Subsystem performs the digital GSM signal processing.
3.8.4. RF Interface
The RF interface communicates with the mobile station’s external RF and analog baseband circuits.
Signals to these circuits control signal gain in the Rx and Tx signal path and maintain The system’s
frequency reference.
3.8.5. Serial Bus Interface(SBI)
The MSM6250A device’s SBI is designed specifically to be a quick, low pin count control protocol for
QUALCOMM’s RTR6250, RFR6200, RFL6200, and PM6650 ASICs. Using the SBI, the RTR6250,
RFR6200, RFL6200, and PM6650 devices can be configured for different operating modes and for
minimum power consumption, extending battery life in Standby mode. The SBI also controls DC
baseband offset errors.
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