Microchip Technology AC164345 Data Sheet

© 2005 Microchip Technology Inc.

DS30177T-page 17

The dsPIC30F Acoustic Echo Cancellation (AEC) 
Library provides a function to eliminate echoes 
generated in the acoustic path between a speaker and 
a microphone. This function is useful for speech and 
telephony applications in which a speaker and a 
microphone are located in close proximity to each other 
and therefore, susceptible to signals propagating from 
the speaker to the microphone resulting in a 
perceptible and distracting echo effect at the far end. It 
is especially suitable for these applications:

• Hands-free Cell Phone Kits

• Speakerphones

• Intercoms

• Teleconferencing Systems

For hands-free phones intended to be used in compact 
environments, such as a car, this library is fully 
compliant with the G.167 standard for acoustic echo 
cancellation.

• Only 2 user functions 

(“AcousticEchoCancellerInit” and 
“AcousticEchoCanceller”), both of which can be 
called from either a ‘C’ or Assembly application 
program

• Full compliance with the Microchip dsPIC30F C30 

C Compiler, Assembler and Linker simple user 
interface – just one library file and one header file 

• Highly optimized Assembly code, utilizing DSC 

instructions and advanced addressing modes

• Echo cancellation for 16, 32 or 64 ms echo delays or 

‘tail lengths’ (configurable)

• Fully tested for compliance with G.167 

specifications for in-car applications

• Audio Bandwidth: 0-4 kHz at 8 kHz sampling rate

• Convergence Rate: Up to 43 dB/sec., typically > 30 

dB/sec.

• Echo Cancellation: Up to 50 dB, typically > 40 dB

• Can be used together with the Noise Suppression 

(NS) Library, since the same processing block size 
(10 ms) is used

•

“dsPIC30F Acoustic Echo Cancellation Library 
User’s Guide” is provided to help the user 
understand and use the library

• Demo application source code is provided with the 

library. Accessory kit available for purchase includes: 
an audio cable, headset, oscillators, microphone, 
speaker, DB9 M/F RS-232 cable and DB9M-DB9M 
Null Modem Adapter and can be used for library 
evaluation

• Contact Microchip sales for FREE evaluation 

samples

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+

 

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Acoustic Echo

Cancellation

FAR END

NEAR END

Far End
Speech

Far End
Speech

Near End
Speech

Near End
Speech

Receive Path

Adaptive

Filter

Send Path

User Application

Echo

SW300060-EVAL dsPIC30F Acoustic Echo Cancellation Library Software License (Evaluation Copy)

SW300060-5K

dsPIC30F Acoustic Echo Cancellation Library Software License (Up to 5K units)

SW300060-25K dsPIC30F Acoustic Echo Cancellation Library Software License (5K to 25K units)

SW300060-100K dsPIC30F Acoustic Echo Cancellation Library Software License (25K to 100K units)

AC300030

Accessory Kit (includes: audio cable, headset, oscillators, microphone, speaker, 
M/F RS-232 cable, DB9M-DB9M Null Modem Adapter)

DS70123

“dsPIC30F Acoustic Echo Cancellation Library Product Overview” 
(Available at: www.microchip.com)