User Guide

Stereo speakers are driven by a discrete digital stereo speaker amplifier that is connected to the single-ended

outputs of the EM ASIC N2200 (shared output with the discrete stereo headphone amplifier). The discrete

stereo speaker amplifier has a differential output configuration.

The internal microphone is connected directly to the single-ended input of the EM ASIC N2200. Signal line is

biased by the EM ASIC N2200.

Nokia AV mono input is connected to the EM ASIC N2200 single-ended input via two switches: data-switch

and video-switch. The input is biased by the EM ASIC N2200.

Audio loop test

Audio paths can be tested via a built-in audio loop test routine. To test a specific audio path, an electrical

test signal can be fed into the mono input of the Nokia AV-connector and looped to specified audio output:

earpiece, stereo speakers or the Nokia AV stereo output. Similarly, an acoustical or an electrical test signal

can be fed into the internal microphone and looped to the Nokia AV stereo output. Loop routines can be

initiated using the audio test interface in the Phoenix service program.

Vibra can be tested by dedicated vibra test in the Phoenix service program.

Table 10 Audio loop test reference results

Audio loop Input terminal Output terminal Frequency Input signal Output signal

XMIC to EAR AV connector Internal earpiece 1kHz 0.1 [V] y [V]

XMIC to IHF AV connector Stereo speakers 2kHz 0.1 [V] y [A]

XMIC to

XEAR AV connector AV connector 1kHz 0.1 [V] y [V]

INTMIC to

XEAR

Internal

microphone AV connector 1kHz 0.01 [V] y [V]

RM-313

BB Troubleshooting and Tuning Guide

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