QuiteQuiet™
Acoustic Echo Cancellation Software
by Atlanta Signal Processors, Inc.

Software Overview

The QuiteQuiet Acoustic Echo Cancellation (AEC) software is an implementation of the AT&T-patented 
acoustic echo cancellation technology. QuiteQuiet AEC technology cancels acoustic echoes arising in 
two-way and multipoint hands-free telephony, providing high-quality, full-duplex speech 
communications for a wide variety of teleconferencing and video-teleconferencing applications

Features and Benefits

•	Adaptively cancels acoustic echoes arising in hands-free audio/video teleconferencing systems.
•	Fast, completely automatic training, continuous adaptation.
•	Provides high-quality, full-duplex speech communications.
•	Supports both 3.5-kHz and 7-kHz speech communications (G.722, G.728, G.729, and others).

Processor and System Specifications

•	The QuiteQuiet AEC is available in object code for the TI TMS320C31 DSP.

Average MIPS
Program/Data
Memory Size
8-kHz sample rate
8
20 k
16-kHz sample rate
16
32 k

Usage Limitations or Performance Considerations

•	Audio Processing Bandwidth:
125–3500 Hz ±2 dB, @ 8-kHz sample rate
125–7125 Hz ±2 dB, @ 16-kHz sample rate
•	Acoustic Echo Compensation length is determined by resource availability; varies with frequency
•	Convergence Rate of Adaptation: 
30 dB/sec.
•	Adaptive (only) Echo Cancellation:
> 45 dB 
•	Total Echo Cancellation:
60 dB, maximum 
•	Room Acoustic Gain:
Up to 10 dB, nominal
•	Software state machine automatically determines each of four states (receive, transmit, 
double-talk, and idle)

Algorithm Verification

•	QuiteQuiet AEC performance specifications are compatible with the ITU's G.165 and G.167 series 
recommendations on echo cancellers for telephony.

Availability

•	The QuiteQuiet AEC algorithm was written by AT&T Corp. and is now available for licensing 
exclusively from Atlanta Signal Processors.

Company Background and Contact Information

Atlanta Signal Processors was founded in 1981 by Ronald W. Schafer, Thomas P. Barnwell III, and 
Russell M. Mersereau, three Professors of Electrical Engineering at the Georgia Institute of 
Technology with over 80 years of experience in the field. The company has focused its efforts on 
developing tools for professional signal-processing design engineers and now offers digital 
signal-processing hardware and software products to DSP designers worldwide.

Contact:	Atlanta Signal Processors, Inc.
		1375 Peachtree St. NE, Suite 690
		Atlanta, Georgia  30309-3115
		(404) 892-7265
		Fax: (404) 892-2512
		e-mail: aspi@aspi.com