Q2686 Wavecom, Q2686 Datasheet - Page 44

• Manufacturer Part Number: Q2686
• Description: Wireless CPU
• Manufacturer: Wavecom

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3.11
Two different microphone inputs and two different speaker outputs are
supported.
The Q2686 Wireless CPU
allows hands-free functionality.
3.11.1 Microphone Inputs
The MIC2 inputs already include the biasing for an electret microphone, thus
allowing easy connection.
The MIC1 input requires external biasing if an electret microphone is used.
3.11.1.1 Common Microphone Input Characteristics
The connection may be either differential or single-ended but
differential connection is strongly recommended, in order to reject common
mode noise and TDMA
a good ground plane, good filtering as well as shielding in order to avoid any
disturbance on the audio path.
The gain in MIC inputs is internally adjusted and may be tuned by using an AT
command.
Both may be configured either as differential or single-ended.
3.11.1.2 Main Microphone Inputs (MIC2)
By default, the MIC2 inputs are differential inputs, but may be configured as
single-ended.
microphone. The electret microphone may be directly connected to these
inputs.
AC coupling is already embedded in the Wireless CPU
This document is the sole and exclusive property of WAVECOM. Not to be distributed or divulged without
prior written agreement.
WM_PRJ_Q2686_PTS_001-007
MIC2N
MIC2P
Signal
Analog Audio Interface
They
number
confidential ©
Pin
36
34
already
noise. When using a single-ended connection, ensure
I/O
®
I
I
also includes an echo cancellation feature, which
MIC2 pin description
include
I/O type
Analog
Analog
convenient
Microphone 2 negative input
Microphone 2 positive input
Q2686 Wireless CPU
biasing
®
Description
.
for
an
Interfaces
using a
electret
March 6, 2007
Page: 43 / 87
®