User Guide

NPE-4
3 - Audio System PAMS Technical Documentation
Page 3-8 ãNokia Corporation. Original
echo canceling.
In case of BT audio the BT accessory and the phone is connected by both an ACL and SCO
air link. ACL is used for connection commands and SCO for the actual audio transmission.
In both cases the BT module (in accessory and phone) receives the audio signal. In the
phone this signal is routed from BT module over LPRF to DSP where it follows the regular
audio path through out the rest of the system. The BT module and MCU is connected by
the CBUS for exchanging low level information.
All BT Gain adjustments are done in the accessory. DSP tuning is done in UPP, completely
as usually.
Gain Table
The possible gain for each input and output is shown in The gain settings are controlled
in the 16 bit AudioCtrlR register. Note * MIC3 only used for test purposes in NPE-4.. Table
4: Total UEM gain for each input and output in different audio paths (modes). contains
the total gain for each input and output in different audio modes.
The gain settings are controlled in the 16 bit AudioCtrlR register.
Note * MIC3 only used for test purposes in NPE-4.
Table 3:
Possible UEM gains for each input and output
UEM Pins Gain (dB)
Input / Output Programmable Fixed UEM Tota l
MIC1 0 to 22.5, step 1.5dB 20 20 to 42.5, step 1.5dB
MIC2 0 to 22.5, step 1.5dB 0 or 20 0 to 22.5 or 20 to 42.5, step 1.5dB
MIC3* 0 to 22.5, step 1.5dB 0 or 20 0 to 22.5 or 20 to 42.5, step 1.5dB
HF (single ended) -30 to 0, step 2dB 6 -24 to 6, step 2dB
EAR -30 to 0, step 2dB 6 -24 to 6, step 2dB
Table 4: Total UEM gain for each input and output in different audio paths (modes)
Gain Table Normal Mode - Gain dB
UEM Signals
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Handportable Headset Handsfree (Carkit)
INPUTS MIC1 20 to 42.5, step 1.5dB
MIC2 20 to 42.5 step 1.5dB 0 to 22,5 step 1.5dB
MIC3
OUTPUTS EAR -24 to 6, step 2dB
HF -24 to 6, step 2dB -24 to 6, step 2dB