Audio Interface - LG KP150Q Service Manual

3.10 Audio Interface

3.10.1 Uplink Path
A voice signal is converted to electrical signal with Microphone. The converted electrical voice signal is
amplified and converted to digital signal in ABB(T3031). The converted digital data is encoded to GSM
voice standard in DBB(LOCOSTO).
The audio signals from main microphone goes to MICP and MICN of ABB and the voice signal from
head-set to HSMIC of ABB. The bias voltage for microphone is 2V for main mic. and 1.8V for head-set
mic, which bias voltage is generated in ABB(MICBIAS, V_IO)
MICIP
MICIN
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
R214
1K
C220 C221
0.1u 10u
L200
C222 22n
100nH
C223
DNI
C224 22n
Figure 3-10-1 Main Mic interface
3. HW Circuit Description
MICBIAS
R225
VA205
DNI
C217
39p
R227 0
C225
DNI
- 31 -
L201
100nH
MIC200
1
OUT
2
G1
3
G2
4
G3
5
PWR
6
G4
SPM0204LE5-QB
LGE Internal Use Only