G.168 v9 Now Available

Adaptive Digital's echo canceller is a robust, carrier class, flexible software solution that is available across a wide variety of DSP platforms. Adaptive Digital's patented algorithm achieves excellent voice quality while leading the industry in CPU and memory utilization efficiency.

Seven years ago, Adaptive Digital upgraded its G.165 echo canceller to meet the International Telecommunications Union (ITU) G.168 recommendation. Two years later, Adaptive Digital submitted its echo canceller for validation testing at AT&T’s Voice Quality Laboratory in Middletown, New Jersey. AT&T’s Voice Quality Assessment Lab evaluated the echo canceller using its stringent series of performance tests including AT&T’s proprietary Mean Opinion Score (MOS) subjective tests as well as the standardized set of G.168 objective tests. The subjective and objective performance of Adaptive Digital’s echo canceller surpassed even the performance of AT&T’s benchmark lab echo cancellers.

Nevertheless, the rigorous testing undergone by Adaptive Digital’s G.168 EC at the AT&T labs in 2002 did not encompass all of the requirements set forth by today’s diverse telephone applications. With today's G.168 version 8, Adaptive Digital strives to meet the current and future requirements of service providers, system integrators and developers, bringing superior voice quality to speech-based applications. By continually evolving their echo cancellation algorithm, Adaptive Digital strives to increase the differentiation between their EC and those of their competitors.

Voice Quality Certification G.168 compliance is just the beginning. The true test of merit of an echo canceller is voice quality. Adaptive Digital's canceller has been tested in-house, by many customers, and independently by AT&T at their Voice Quality Test Lab (2004). AT&T performed both G.168 objective tests and Mean Opinion Score (MOS) subjective tests. Adaptive Digital's canceller fared better than industry standard cancellers under the most important and difficult conditions: double-talk and the presence of background noise. Version 8 expands the functionality of the echo canceller to meet the varying needs in today’s diverse telecommunication landscape.

KEY:

EC

A- Adaptive Digital's patended ADT G.168 EC
X & Z - 2 industry standard Echo Cancellers

EC

CONDITION

MOS
Z Convergence 4.52

A

Convergence

4.58*
X Convergence 4.16
Z Double - Talk 2.56

A

Double - Talk

3.24*
X Double - Talk 3.00
Z Convergence in Noise 2.95

A

Convergence in Noise

3.14*
X Convergence in Noise 2.65

* Testing results 2004 G.168 v7

MOS - Mean Opinion Score - This is a formally tested subjective measure of speech quality. The scale goes as high as 5.0, which is the rating for uncompressed speech (8 K samples/sec with 16 buts per sample).

ECHO TAIL

The length of time over which echo may arrive is known as the echo tail length. The impulse response of the echo path tends to be spread over a 4-8 millisecond range, but the location within the entire echo tail of this 4-8 milliseconds may not be known. This is due to a variety of sources of delay in the telephone system. With the proliferation of VoIP telephone systems, we can see large delays as a result of the delay in the packet network itself. Adaptive Digital's algorithm can operate with delays as high as 256 milliseconds

ECHO CANCELLER REQUIREMENTS

When a call is first established, an echo canceller has no idea about the nature of the echo path. With the first utterance of speech (or other sound) and presence of its echo, the echo canceller must adapt to the echo path quickly in order to cancel the echo. The adaptation process is referred to as convergence and the amount of time required to adapt is referred to as the convergence time. Even after initial convergence, the echo canceller must monitor the echo path for potential changes in characteristics caused by events such as adding or dropping a party from a conference call, PCM slips, redundancy fail-over, etc. In addition, the canceller must be capable of detecting the presence of signaling tones as well as fax and modem signals and act appropriately. Although compliance with the ITU G.168 recommendation is required, it is just the beginning. It is well known that a canceller can be compliant with G.168 yet still exhibit poor voice quality under many circumstances. Many cancellers may boast G.168 compliance, but only be compliant under tame hybrid conditions. Some are even tuned just to pass G.168 tests while sacrificing voice quality in the process. Adaptive Digital's canceller meets or exceeds all the G.168 tests in the presence of all 8 G.168 hybrid models while maintaining superior voice quality as the primary goal.

THE ADAPTIVE DIGITAL SOLUTION

Adaptive Digital's echo canceller is deployed in over forty countries in carrier, enterprise, satellite, and wireless systems. While many cancellers require hundreds of milliseconds to converge, Adaptive Digital's proprietary Nyquist Transform Adaptation Accelerator enables its canceller to converge within 75 milliseconds 99 percent of the time.

PRODUCT PORTFOLIO

Adaptive Digital's canceller can be licensed in a number of ways:

A "C" callable object library can be licensed and integrated into a customer's own application framework. This library is available today on a variety of popular DSPs as well as on the Windows platform. It can be ported to any DSP or RISC chip. Assembly source code is available to qualified customers.

Adaptive Digital's turnkey echo canceller solution provides the customer a multi-channel echo canceller chip solution. The solution can be scaled based upon required channel density by selecting the appropriate DSP chip.

Adaptive Digital's echo canceller is available as part of the following DSP chip solutions:

Adaptive Digital's fixed-point "C" reference code is available to qualified customers who wish to port the algorithm to proprietary DSP or ASIC chip. The fixed-point "C" code is a bit-exact implementation and hence shares the performance and robustness of our DSP implementations. Unlike our larger competitors, we cater to companies of all sizes. We understand the differing business requirements and therefore offer the right business model for each customer. upport and Quality Assurance

Adaptive Digital supports customers from evaluation through integration, deployment, and throughout the product lifecycle. It is this close relationship with customers in the past that has enabled us to make our canceller robust under a wide variety of real-world conditions.

Many echo canceller vendors buy and re-license the underlying technology, and are therefore far less adept at supporting the canceller beyond simple software integration. Our canceller technology has been developed exclusively with in-house expertise and is supported by the same engineers who have worked to develop it over the years. We can therefore provide support at the system level as well as the software level.

Adaptive Digital fielded its first echo canceller in 1995. Over the years, we have continually made improvements to both voice quality and efficiency. After having deployed the canceller for so many years and having seen the types of problems that arise under real-world conditions, we have a process in place for analyzing field problems and resolving them whether they are due to algorithm configuration parameters or due to external factors. As a result of this experience, we have incorporated the appropriate user controllable parameters, and we assist customers in adjusting these parameters based upon feedback from the lab or from the field.

TIME TO MARKET

By making use of our extensive documentation and our support, many customers are able to integrate our echo canceller into their framework in less than one day. The key to that success is a combination of a well-designed, well-documented API and a responsive support infrastructure. We believe engineers should spend their time developing and testing the end product rather than dealing with idiosyncrasies that exist in so many DSP algorithm implementations.

Sample Channel Densities:

DSP C5409A C5416 C5421 C5441 C5509 C641X
Density 24 32 40 96 48 256

 

 

 




Adaptive Digital Technologies, Inc.

DEPLOYED IN OVER 40 COUNTRIES

TESTIMONIAL ~ After evaluating numerous G.168 echo cancellers, IPC (formally Global Crossing) has licensed Adaptive Digital's for use in our sophisticated telephone equipment that is used by stock exchanges around the world. Our customers are the most critical of voice quality, hence this was the most important factor in choosing Adaptive Digital's echo canceller. It was the only one that operated flawlessly under all possible conditions. The second factor in making the decision was echo canceller's low processing requirements, which results in high channel density and lower cost.
Alex Wissink ~ Manager, IPC (Global Crossing)



ECHO CANCELLATION SUBJECTIVE TESTING DEMO

"At Adaptive Digital, we recognized long ago the impact that voice quality has on telephone users. Whether speaking with family, friends, or business colleagues, the telephone network must provide a conduit for clear, comfortable conversation," said Scott Kurtz, Adaptive Digital's Vice President. "We are both proud and pleased to learn that our attention to voice quality has yielded us an echo canceller that exceeds the requirements of AT&T, the company whose network historically defined the term "carrier class."


Scott Kurtz, VP Engineering

 

 

PRODUCTS