Nokia 7370, Руководство по обслуживанию

Страница: 200 / 226

Internal microphone
Internal microphone is used for HandPortable (HP) and Internal HandsFree (IHF) call modes.
An analogue electret microphone is connected to N2200 Mic1P and Mic1N inputs via asymmetric electrical
connection.
The microphone is biased by N2200 MicB1 bias voltage output.
Figure 61 Internal microphone circuitry
External microphone
Galvanic accessories are connected to the system connector (Pop-Port
TM
).
Accessory audio mode is automatically enabled/disabled during connection/disconnection of dedicated
phone accessories.
External microphone circuitry is biased by Retu ASIC MicB2 bias voltage output. The circuitry provides a
symmetrical connection for the microphone from the Pop-Port
TM
connections, XMICN and XMICP, to Retu ASIC
inputs, Mic2P and Mic2N.
Internal earpiece
Internal earpiece is used for the HandPortable (HP) call mode. A dynamic earpiece capsule is connected to
Retu's differential output EarP and EarN.
Internal speakers
Internal speakers are used for Internal HandsFree (IHF) call mode, ringing tones, FM-radio and music listening.
Two dynamic 13mm speakers are connected to Retu ASIC’s outputs XearR/XearL via stereo D-class IHF
amplifier TPA2012D2.
The amplifier has 24 dB fixed gain and it is put to shutdown mode when not in use.
RM-70
Nokia Customer Care System module
Page 8 –18 COMPANY CONFIDENTIAL Issue 1
Copyright © 2005 Nokia. All rights reserved.