Audio Circuit Design - Quectel GSM Series Audio Design Manual

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Audio Circuit Design

M1x and M95 have two hardware audio channels except M80. Three audio channels are defined in
software. AT+QAUDCH is used to read and set the software audio channel. This chapter provides audio
interface circuit and some solutions to resolve TDD noise and ECHO issues.
Table 1：Audio Hardware Configuration
(AIN1/AOUT1)
Module
MIC
&
Differential
M1x
Internal Bias
&
Differential
M95
Internal Bias
&
Differential
M80
Internal Bias
Notes
1. M95 module has built-in class AB amplifier and also supports voice and ringtone at channel AOUT2.
2. M80 module supports voice and ringtone at channel AOUT2. AOUT1 and AOUT3 can also output
ringtone but via AT+QRCH=1(only used at M80).
3. M80 module has built-in class AB amplifier at channel AOUT3, and the maximum power is 800mW.
GSM Module Audo Design Guide
SPK MIC
Differential
Differential
Internal Bias
Differential
Differential
Internal Bias
Differential
Differential
Internal Bias
Confidential/Release
GSM Module Audio Design Guide
(AIN2/AOUT2)
SPK
&
Signal-end
&
Differential
&
Signal-end
GSM/GPRS Modules
AOUT3
SPK
/
/
Differential
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