LG VX11000 Service Manual page 35

VX11000
2.3 Circuit Description
2.3.1 Keypad/LCD and Receptacle Part
Once the main keypad is pressed, the key signals are sent out to MSM7500A for processing. Touch keypad is pressed,
Ack signals are sent out to MSM7500A for processing. In addition, when the key is pressed, the keypad/LCD lights
up through the use of 19 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 MSM7500A) 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
MSM7500 activate the ringer by using signals generated in the timer in MSM7500.
2.3.3 MSM Part
The MSM7500A device integrates the ARM1136-J™ and ARM926EJ-S™ processor cores, offering the ARM®
Jazelle™ Java® hardware accelerator: one low-power, high-performance QDSP5000™ application digital signal
processor (aDSP) and one QDSP4000™ modem digital signal processor (mDSP) core, hardware acceleration for
video, imaging, and graphics, and a wideband stereo codec to support enhanced digital audio applications. The
hardware acceleration eliminates the need for the multimedia companion processors normally required for video and
audio-based applications that support MP3 music files, a MIDI synthesizer, video and still image record and playback,
and 2D/3D graphics functions. By removing the need for costly applications coprocessors and memory subsystems,
the MSM7500A solution reduces BOM costs and increases standby and talk times. QUALCOMM provides a
complete software suite and advance mobile subscriber software (AMSS) for building handsets based on the
MSM7500A chipset. AMSS software is designed to run on a SURF phone platform, an optional development
platform optimized to assist in evaluating, testing, and debugging AMSS software.
LG Electronics Inc.
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