LG MG120a Service Manual page 28

3. TECHNICAL BRIEF
3.3.6 Microphone
The microphone is placed to the A side of PCB. The audio signal is passed to VINNOP
and VINNON pins of AD6720. The voltage supply VMIC is output from AD6720, and is a
biased voltage for the VINNOP. The VINNOP and VINNON signals are then A/D
converted by the voiceband ADC part of AD6720.The digitized speech (PCM
8KHz ,16KHz) is then passed to the DSP section of AD6720 for processing (coding,
interleaving etc).
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