Service Manual
9LWHOFRP0REL O H7HFKQRORJ\6$ 3URSULHWDU\DQG&RQILGHQWLDO - 16 -
V
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Figure 4.7 TX_BBA Functional Block Diagram
4.3 Logic Part Description
The logic part processes the user’s commands and processes all the digital in order to operate in the
phone. The logic part is made up of a keypad/ LCD, receptacle part, voice processing part, mobile station
modem(MSM, U125) part, memory part(U113), and power supply part.
4.3.1 Keypad/ LCD
This is used to transmit keypad signals to MSM(U125).
It is made up of a keypad backlight part that illuminates the keypad, LCD part that displays the operation
status onto the screen, and a receptacle that receives and sends out voice and data with external sources.
4.3.2 Voice Processing Part
The voice processing part is made up of an audio codec and an amplifier used to convert MIC(CON102)
signals into digital voice signals and digital voice signals into analog voice signals.
4.3.3 Mobile Station Modem( MSM, U125)
The MSM(U125) integrates functions that support a CDMA subscriber unit. Subsystems within the
MSM(U125) include a CDMA processor, a QUALCOMM Code Excited Linear Predication (QCELP)
Vocoder, an Enhanced Variable Rate CODEC (EVRC) Vocoder, an ARM7TDMI microprocessor, and
assorted peripheral interfaces that are used to support other functions.