LG LG-UD90c, Service Manual

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LG-KG90C
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2.2.4 Memory Part
The memory part is made up of a flash memory, SDRAM for storing data.
2.3 Circuit Description
2.3.1 Keypad/LCD and Receptacle Part
Once the keypad is pressed, the key signals are sent out to MSM6100 for processing. In addition,
when the key is pressed, the keypad/LCD lights up through the use of LEDs. The terminal status and
operation are displayed on the screen for the user with the characters and icons on the LCD.
Moreover, it exchanges audio signals and data with external sources through the receptacle, and then
receives power from the battery or external batteries.
2.3.2 Audio Processing Part
MIC signals are amplified through OP AMP, inputted into the audio codec(included in MSM6100) and
converted into digital signals. Oppositely, digital audio signals are converted into analog signals after
going through the audio codec. These signals are amplified at the audio amplifier and transmitted to
the ear-piece. The signals from MSM6100 activate the ringer by using signals generated in the timer
in MSM6100.
2.3.3 MSM Part
The MSM6100 chipset integrates functions that support both tri-mode CDMA/FM and cellular-only
handset operation. Subsystems within the MSM6100 baseband processor device include a CDMA
processor, digital FM (DFM) processor, QCT’s latest generation of DSP, the QDSP4000™ core, for
voice compression and applications support, PLL and an ARM® ARM926EEJ-S microprocessor. Also
integrated in the MSM6100 device are analog functions such as a wideband mono codec and analog
interfaces for the radioOne RF ASICs. Controllers for a universal serial bus (USB), device controller
for an R-UIM (CDMA SIM), GPIOs, and peripheral interfaces complete the system integration. And the
MSM6100 chipset and system software are designed to support IS95A/95B and Release 0 of
CDMA2000 standards.
In MSM, coded symbols are interleaved in order to cope with multi-path fading. Each data channel is
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