GAO Acoustical Echo Canceller
by GAO Research & Consulting Ltd.

Software Overview

Acoustical echo canceller is the key component in a full-duplex speakerphone. A significant amount 
of research has been performed to develop highly-effective and efficient adaptive acoustical echo 
cancellers. GAO Acoustical Echo Cancellers are the results of these research efforts.

Features and Benefits

•	Implemented in the assembly
•	Low data, program memory, and computational requirements
•	Robust double-talk detection

Processor and System Requirements

•	Devices supported: TMS320C3x, TMS320C5x, TMS320C54x
•	Algorithm category: Telecommunications
•	Required:
Maximum echo duration:
About 200 ms
Average ERLE:
>40dB
Program memory:
0.7–2.5 kwords (echo duration from 20 ms to 200 ms)
Data memory:
0.3–2.0 kwords (echo duration from 20 ms to 200 ms)
MIPS:
4–30 MIPS (echo duration from 20 ms to 200 ms)

Algorithm Verification

•	Meet or exceed the requirements of ITU G.167 standard which consists of a set of standard tests 
for acoustical echo cancellers.

Availability

•	The software is available now and demonstration is available at GAO's offices in Toronto, Canada.

Company Background and Contact Information

GAO Research & Consulting Ltd. is an established international supplier of DSP algorithms, 
software, and systems for the telecommunications market. It provides a complete line of telephony, 
fax, and modem solutions. Its products have been widely reported by over 30 leading publications in 
the industry.
GAO currently employs about 20 DSP engineers. It was founded in 1991 and has been managed by Dr. 
Frank X.Y. Gao.
Contact:	Dr. Frank X.Y. GAO, CEO
		GAO Research & Consulting Ltd.
		55 Nugget Avenue, Unit 204
		Scarborough,  Toronto
			Ontario, Canada M1S 3L1
		(416) 292-0038
		Fax: (416) 292-2364
		e-mail: gao@io.org
		www: http://www.io.org/~gao