Nokia NSB-9 Service Manual page 23

CCS Technical Documentation
audio signals to and from the user interface. The UEM supplies the analog TXC and AFC
signals to RF section according to the UPP DSP digital control. Data transmission
between the UEM and the UPP is implemented using two serial busses, DBUS for DSP and
CBUS for MCU. RF ASIC, Hagar, is controlled through UPP RFBUS serial interface. There is
also separate signals for PDM coded audio. Digital speech processing is handled by the
DSP inside UPP ASIC. UEM is a dual voltage circuit, the digital parts are running from the
baseband supply 1.8V and the analog parts are running from the analog supply 2.78V
also VBAT is directly used by flip, stereo amplifier, IR and some other blocks.
The baseband supports both internal and external microphone inputs and speaker out-
puts. UEM also includes third microphone input which is used in NSB-9 for FM radio
with IHF use (Left channel). Input and output signal source selection and gain control is
done by the UEM according to control messages from the UPP. Keypad tones, DTMF, and
other audio tones are generated and encoded by the UPP and transmitted to the UEM for
decoding. An external vibra alert control signal is generated by the UEM with separate
PWM outputs.
NSB-9 has two external serial control interfaces: FBUS and MBUS. These busses can be
accessed only through production test pattern.
EMC shielding for baseband is implemented using a metal shielding can. Although some
components are outside the shielding can. On the other side the engine is shielded with
PWB grounding. Heat generated by the circuitry will be conducted out via the PWB
ground planes.
Full functionality according to the specifications needs to be met through ambient tem-
perature range -10 °C to +55 °C. Storage temperature range -40 °C to +85 °C.
Issue 1 04/03
System Module and User Interface
Nokia Corporation
NSB-9
Page 9