Nokia 2600 服务手册
RH-59/60
Nokia Customer Care
7-System Module
20
COMPANY CONFIDENTIAL
ISSUE 1 09/2004
Copyright © 2004 Nokia. All Rights Reserved.
The earpiece circuit includes only a few components:
two 10 ohm in order to have a stable output
an EMC filter
Figure 4:Earpiece interface
Microphone
An omni directional microphone is used. The microphone is placed in the system connector
sealed in its rubber gasket. The sound port is provided in the system connector.
sealed in its rubber gasket. The sound port is provided in the system connector.
Figure 5:Bottom connector including the microphone
The microphone connection comprises a differential bias circuit, driven directly from the MICB1
bias output with external RC-filters.
bias output with external RC-filters.
The RC filter (220
Ω, 4.7µF) is scaled to provide damping at 217 Hz.
EARN
EARP
EARP
EARN
UEM
10
ohm
10
ohm
Placed near UEM
Placed in top of
PWB, near
earpiece