Quectel GSM Series Audio Design Manual Download

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GSM

Module

Audio Design Guide

GSM/GPRS Series

Version: GSM_Module _Audio_Design_Guide_V3.0

Date: 2013-05-24

www.quectel.com

Summary of Contents for GSM Series

Page 1: ...GSM Module Audio Design Guide GSM GPRS Series Version GSM_Module _Audio_Design_Guide_V3 0 Date 2013 05 24 www quectel com...

Page 2: ...S BASED UPON CUSTOMERS REQUIREMENTS QUECTEL MAKES EVERY EFFORT TO ENSURE THE QUALITY OF THE INFORMATION IT MAKES AVAILABLE QUECTEL DOES NOT MAKE ANY WARRANTY AS TO THE INFORMATION CONTAINED HEREIN AND...

Page 3: ...2009 11 02 Tracy Zhang Initial version 1 1 2009 11 20 Tracy Zhang 1 Added some acronym 2 Added a Audio Power Amplitude manufacturer 3 Added a solution to TDD noise 4 Modified cover 1 2 2010 11 20 Roy...

Page 4: ...nce Circuit 14 2 1 3 3 SPK Reference Circuit 15 2 1 4 M80 16 2 1 4 1 Microphone Reference Circuit 16 2 1 4 2 Receiver Reference Circuit 16 2 1 4 3 Headset Reference Circuit 18 2 1 4 4 SPK Reference Ci...

Page 5: ...GSM GPRS Modules GSM Module Audio Design Guide GSM Module Audo Design Guide Confidential Release 4 35 4 Appendix A 35 Quectel Confidential...

Page 6: ...ule Audio Design Guide GSM Module Audo Design Guide Confidential Release 5 35 Table Index TABLE 1 AUDIO HARDWARE CONFIGURATION 9 TABLE 2 REFERENCE DOCUMENT 35 TABLE 3 DESCRIPTION OF ECHO AND TDD NOISE...

Page 7: ...CIRCUIT FOR AIN1 AIN2 13 FIGURE 8 RECEIVER REFERENCE CIRCUIT FOR AOUT1 14 FIGURE 9 HEADSET REFERENCE CIRCUIT 14 FIGURE 10 SPK REFERENCE CIRCUIT 15 FIGURE 11 MICROPHONE REFERENCE CIRCUIT FOR AIN1 AIN2...

Page 8: ...ilure to comply with these precautions Full attention must be given to driving at all times in order to reduce the risk of an accident Using a mobie while driving even with a handsfree kit cause distr...

Page 9: ...service area with adequate cellular signal strength Your cellular terminal or mobile contains a transmitter and receiver When it is ON it receives and transmits radio frequency energy RF interference...

Page 10: ...2 AOUT2 AOUT3 MIC SPK MIC SPK SPK M1x Differential Internal Bias Differential Differential Internal Bias Signal end M95 Differential Internal Bias Differential Differential Internal Bias Differential...

Page 11: ...rence circuit is shown as below 10pF 33pF 33pF 33pF Close to Microphone MICxP MICxN Differential layout Electret Microphone GND GND 10pF 10pF ESD ESD Module Figure 1 Microphone Reference Circuit for A...

Page 12: ...Differential layout 10pF 10pF 33pF 33pF 33pF Close to speaker GND GND 10pF Module ESD ESD Figure 2 Receiver Reference Circuit for AOUT1 SPK1P SPK1N Differential layout Amplifier circuit 10pF 10pF 33pF...

Page 13: ...GND Module 22uF ESD Figure 4 SPK Reference Circuit for AOUT2 Module SPK2P AGND Differential layout Amplifier circuit 10pF 10pF 33pF 33pF Close to speaker GND GND C2 C1 ESD ESD Figure 5 Receiver Refer...

Page 14: ...3pF GND 10pF ESD Figure 6 Headset Reference Circuit 2 1 2 M95 2 1 3 Microphone Reference Circuit M95 module provides electrets microphone bias voltage for AIN1 and AIN2 Reference circuit for microphon...

Page 15: ...10pF ESD ESD Module Close to Receiver GND Figure 8 Receiver Reference Circuit for AOUT1 2 1 3 2 Headset Reference Circuit 1 2 4 3 Amphenol 9001 8905 050 MIC2P 22uF 68R 33pF GND AGND Close to Socket 33...

Page 16: ...dule Audo Design Guide Confidential Release 15 35 2 1 3 3 SPK Reference Circuit LOUDSPKN ESD ESD 0R 0R LOUDSPKP 8 ohm Module GND Close to Speaker 10pF 33pF 33pF 10pF 10pF 33pF GND Differential layout...

Page 17: ...for microphone is illustrated as following figure 10pF 33pF 33pF 33pF Close to Microphone MICxP MICxN Differential layout Module Electret Microphone GND GND 10pF 10pF ESD ESD Figure 11 Microphone Refe...

Page 18: ...D Figure 13 SPK Reference Circuit for AOUT2 SPK2P AGND Differential layout Amplifier circuit 10pF 10pF 33pF 33pF Close to speaker ESD ESD Module C2 C1 GND GND Figure 14 SPK Reference Circuit with audi...

Page 19: ...8905 050 SPK2P MIC2N MIC2P 22uF 68R 33pF GND AGND Close to Socket Differential layout 33pF AGND 33pF 10pF GND Module 4 7uF ESD ESD Figure 15 Headset Reference Circuit 2 1 4 4 SPK Reference Circuit LOU...

Page 20: ...1 but support to output ringtone via channel AOUT2 M95 outputs ringtone via channel AOUT2 by default M80 outputs ringtone via channel AOUT2 by default channel AOUT1 can output ringtone via AT QAUDCH 0...

Page 21: ...mode noise SPK circuit is recommended as following IN IN SHUT_DOWN BYPASS VO VO GND VDD C312 10pF C311 10pF 10pF C313 C4 33pF C2 33pF C3 33pF VBAT FB301 FB302 Close to speaker C19 10uF C20 33uF 5 8 SP...

Page 22: ...Figure 18 shows an example Figure 18 Layout of Audio 2 5 TDD Noise Solution It is important to avoid or reduce TDD noise in audio circuit design and layout This chapter provides some solution to resol...

Page 23: ...at PCB or else it could lead to TDD noise 6 Antenna must be stay away from audio components and layout of audio circuit Keep the distance at least 5cm from antenna to microphone 7 Layout of power supp...

Page 24: ...ress the inner echo interference Figure 20 shows recommended design for microphone socket Figure 20 Microphone Socket Design The best installation way of microphone socket is to encase microphone by s...

Page 25: ...ith sufficient space could produce a good voice output An 8 speaker is often big and difficult to give an independently sealed rear cavity for it However sealing microphone socket in chassis is always...

Page 26: ...of 32 receiver 16 receiver or 8 speaker is recommended These technical data are often shown in data sheet of SPK and receiver For SPK its frequency response and THD performance can be tested by speak...

Page 27: ...rison the green one performs the best and the blue one is second and the red one is the worst 2 8 Component of Microphone It is recommended to use an electret microphone with a sensitivity of 42 3dB P...

Page 28: ...M80 has three audio channels in hardware named AIN1 AOUT1 AIN2 AOUT2 and AOUT3 Channel AOUT3 is used as output of hands free application Software channel 0 is applied as hardware channel AIN1 AOUT1 S...

Page 29: ...o channel default 1 Headset audio channel 2 Loudspeaker audio channel AT QMIC a Test Command AT QMIC Response QMIC list of supported channel s list of supported gain level s OK Read Command AT QMIC Re...

Page 30: ...n level is too high receiving distortion would happen gain level Range is 0 15 AT CLVL Test Command AT CLVL Response CLVL list of supported level s OK Read Command AT CLVL Response CLVL level OK Write...

Page 31: ...sted in hands free application AT QSIDET Test Command AT QSIDET Response QSIDET list of supported gainlevel s OK Read Command AT QSIDET Response QSIDET NORMAL_AUDIO gainlevel OK QSIDET HEADSET_AUDIO g...

Page 32: ...ra1 para2 para3 setting Response If op is read QAPS result list OK If op is write OK If format is error response CME ERROR err op Operation 0 Get old value 1 Set new value para1 Type of parameters 0 I...

Page 33: ...udio parameters of normal audio mode software channel 0 QAPS 4 0 96 253 16388 31 57351 31 400 0 80 4325 99 0 20488 0 0 8192 OK AT QAPS 0 4 1 Read audio parameters of headset audio mode software channe...

Page 34: ...ue caused by bad circuits or mechanical structure Some of parameters can be modified to fix echo issue Advices of audio parameters in different application are provided in the next section 3 1 3 1 Des...

Page 35: ...0 0 80 4325 99 0 8223 0 0 8192 AT QAPS 1 4 0 192 253 5256 31 57351 31 400 0 80 4325 99 0 8223 0 0 8192 AT QAPS 1 4 0 192 253 2218 31 57351 31 400 0 80 4325 99 0 8223 0 0 8192 AT QAPS 1 4 0 248 253 221...

Page 36: ...t unsealed mechanical structure high SPK loud voice or high sensitivity microphone ECHO issue has a negative effect on talking TDD noise TDD noise could be present at the far end of the near end while...

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