Functional Description; Fig 3 Audio Control - Nokia NSB-7 Series Service Manual

NSB-7
UI Module

Functional Description

Audio Control
The audio control and processing is taken care of by the COBBA-GJP, which contains the
audio and RF codecs, and the MAD2, which contains the MCU, ASIC and DSP blocks han-
dling and processing the audio signals.
Bias +
EMC
MICP/N MIC2
MIC1
MIC3
EMC + Acc.
Interf.
XMICP/N
XEARP/N
HFCM
AuxOut
EMC HF
EARP/N
The baseband supports three microphone inputs and two earphone outputs. The inputs
can be taken from an internal microphone, a headset microphone or PPH-1 microphones.
The microphone signals from different sources are connected to separate inputs at the
COBBA-GJP ASIC. Inputs for the microphone signals are differential type.
The MIC1 inputs are used for a headset microphone that can be connected directly to the
HS/HF connector. The internal microphone is connected to MIC2 inputs. In COBBA there
are also three audio signal outputs of which dual ended EAR lines are used for internal
ear piece and HF line accessory audio output. The third audio output AUXOUT is used for
bias supply to the headset microphone. PData(2) is used for PPH-1 mute control.
The output for the internal earphone is a dual ended type output capable of driving a
dynamic type speaker. The output for the external accessory and the headset is dual
ended (differential). Input and output signal source selection and gain control is per-
formed inside the COBBA-GJP ASIC according to control messages from the MAD2. Key-
pad tones, DTMF, and other audio tones are generated and encoded by the MAD2 and
transmitted to the COBBA-GJP for decoding.
Page 8
COBBA
Preamp
Premult. Multipl.
Pre
& LP
Amp
Multipl.
LP
Figure 3: Audio Control
ãNokia Mobile Phones Ltd.
PAMS Technical Documentation
MAD
DSP MCU
A
D
D
A
Buzzer
Driver in
UISWITCH
Buzzer
Issue 1 06/00