Internal Speaker; Integrated Hands Free - Nokia NSB-9 Service Manual

CCS Technical Documentation

Internal Speaker

The internal earpiece is mounted into the LCD metal frame. The earpiece is a dynamic
earpiece with a 32 ohm impedance. The earpiece is low impedance one since the sound
pressure is to be generated using current and not voltage as the supply voltage is
restricted to 2.7V. The earpiece is driven directly by the UEM. The earpiece driver in UEM
is a bridge amplifier.
UEM
EARP
EARN
27p

Integrated Hands Free

Integrated Handsfree (IHF) makes it possible to keep the phone for example on desk and
keep both hands free. When IHF mode is activated, internal microphone is used as in HP-
mode and IHF speaker is used instead of earpiece.
The FM-radio can be listened from the IHF speaker as well, if a headset is connected
(FM-radio antenna).
The stereo audio amplifier supports four inputs and three outputs. It is capable of deliv-
ering 340mW of continuous averahe power into a mono 8Ohm bridged-tied load and
25mW per channel of continuous average power into stereo 32Ohm loads (when using
3V supply voltage). Stereo signal from FM-radio is connected to Rin and Lin inputs, and
XEAR signal from UEM is connected to PhoneInHS input of stereo audio amplifier. Phone
IHF line includes discrete RC high-pass filtering in order to cut off low frequencies from
IHF speaker. SPKROut lines are connected to IHF speaker. PhoneInIHF to SPKROut path
has fixed 12dB gain.
Issue 1 04/03
Figure 14: Internal speaker
connections
27p
Nokia Corporation
System Module and User Interface
2x1000 Ω Ω Ω Ω @100MHz
NSB-9
8mm PICO
5140247
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