LG VX5400, Service Manual

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2.2.2 Voice Processing Part
The voice processing part is made up of an audio codec used to convert MIC signals into digital voice signals
and digital voice signals into analog voice signals, amplifying part for amplifying the voice signals and sending
them to the ear piece, amplifying part that amplifies ringer signals coming out from MSM6100, and amplifying
part that amplifies signals coming out from MIC and transferring them to the audio processor.
2.2.3 MSM (Mobile Station Modem) 6100 Part
MSM is the core elements of CDMA terminal and carries out the functions of CPU, encoder, interleaver,
deinterleaver, Viterbi decoder, Mod/Demod, and vocoder.
2.2.4 Memory Part
The memory part is made up of a NAND Flash memory, SDRAM for storing data.
2.2.5 Power Supply Part
The power supply part is made up of circuits for generating various types of power, used for the digital/voice
processing part.
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 20 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.
Copyright@2007 LG Electronics. Inc. All right reserved. LGE Internal Use Only
Only for training and serving purposes
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