Internal Microphone - Nokia 6680 RM-36 Service Manual

RM-36
System Module Nokia Customer Care
Figure 114 Audio block diagram

Internal microphone

Internal microphone is used for HandPortable (HP) and Internal HandsFree (IHF) call modes.
An analogue electret microphone is connected to Retu ASIC's Mic1P and Mic1N inputs via asymmetric electrical
connection.
The microphone is biased by Retu ASIC MicB1 bias voltage output.
Figure 115 Internal microphone circuitry
Issue 1 Company Confidential Page 9–27
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