Quectel GSM Series - Page 7

GSM/GPRS Modules
GSM Module Audio Design Guide
GSM Module Audo Design Guide Confidential/Release 6 / 35
Figure Index
FIGURE 1：MICROPHONE REFERENCE CIRCUIT FOR AIN1&AIN2 ........................................................... 10
FIGURE 2: RECEIVER REFERENCE CIRCUIT FOR AOUT1 .......................................................................... 11
FIGURE 3: RECEIVER REFERENCE CIRCUIT WITH AUDIO POWER AMPLIFIER FOR AOUT1 ................. 11
FIGURE 4：SPK REFERENCE CIRCUIT FOR AOUT2 ................................................................................... 12
FIGURE 5：RECEIVER REFERENCE CIRCUIT WITH AUDIO POWER AMPLIFIER FOR AOUT2 .............. 12
FIGURE 6：HEADSET REFERENCE CIRCUIT............................................................................................... 13
FIGURE 7：MICROPHONE REFERENCE 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 ......................................................... 16
FIGURE 12：RECEIVER REFERENCE CIRCUIT FOR AOUT1 ...................................................................... 16
FIGURE 13：SPK REFERENCE CIRCUIT FOR AOUT2 ................................................................................. 17
FIGURE 14：SPK REFERENCE CIRCUIT WITH AUDIO POWER AMPLIFIER FOR AOUT2 ........................ 17
FIGURE 15：HEADSET REFERENCE CIRCUIT............................................................................................. 18
FIGURE 16：SPK REFERENCE CIRCUIT ...................................................................................................... 18
FIGURE 17：HANDS-FREE REFERENCE CIRCUIT AT CHANNEL AIN1/AOUT1 ......................................... 20
FIGURE 18：LAYOUT OF AUDIO .................................................................................................................... 21
FIGURE 19：FIVE ECHO PATHS ..................................................................................................................... 22
FIGURE 20：MICROPHONE SOCKET DESIGN ............................................................................................. 23
FIGURE 22：SPK FREQUENCY RESPONSE................................................................................................. 25
FIGURE 23：SPK THD ..................................................................................................................................... 26
Quectel
Confidential