Microphone; Earpiece - LG 512W Service Manual

3. TECHNICAL BRIEF

3.12 Microphone

The microphone is soldered to the main PCB. The audio signal is passed to VINNORP (#K8) and
VINNORN (#K7) pins of the AD6522. The voltage supply 2V45_VAN is output from the ADP3408,
and is a bias voltage for both the VINNOR (through R41) and VINAUX (through R54) lines. The
VINNOR or VINAUX signal is then A/D converted by the Voiceband ADC part of the AD6521. The
digitized speech is then passed to the DSP section of the AD6522 for processing (coding,
interleaving etc.).

3.13 Earpiece

The earpiece is driven directly from the AD6521 VOUTNORP (#J10) and VOUTNORN (#K10)
pins and the gain is controlled by the PGA in the AD6521. The earpiece is located in the handset
folder front panel, and the signals are routed to it via FPCB connector between Main Board and
FPCB board.
Figure 3-14. Microphone.
Figure 3-15. Earpiece.
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