3.13 Microphone
The microphone is placed to the front cover and contacted to main PCB. The audio signal is passed to VINNORP (#J10) and VINNORN (#K10) pins of AD6525. The voltage supply 2V55_VAN is output from ADP3522, and is a bias voltage for the VINNORP. The VINNOR or VINAUX signal is then A/D converted by the Voiceband ADC part of AD6521. The digitized speech is then passed to the DSP section of AD6525 for processing (coding, interleaving etc.).
