Microphone; Receiver/Speaker/Buzzer - LG B1300 Service Manual

2-12 Microphone

A microphone holder is mounted on PCB and is used to hold the microphone between frond
cover and PCB. The audio signal is passed to the MICIN of Nausica_CS. The voltage supply
MICBIAS is coming from Nausica_CS., and is a bias voltage for both the MICIP and AUDIO_
IN lines form system connector. The MICIN and AUDIO_IN signal is then A/D converted by
the voiceband codec of Nausica_CS. The digitized speech is then passed to the DSP of
Hercrom20 for processing (coding, interleaving etc.).

2-13 Receiver/Speaker/Buzzer

The low impedance speaker is driven by an audio amplifier. The audio amplifier is controlled
by the SHUTDOWN pin form Hercrom20. In normal off-hook, the audio amplifier is turned on,
when the headset is plugged in , the audio amplifier is turned off. When on-hook, the audio a
mplifier is turned off for power saving. There are two audio path (EARP & AUXOP) coming
from Nausica_CS. In Receiver mode, the audio input is fed with EARP, In Speaker/Buzzer
mode, the audio input is fed with AUXOP.
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