echo cancellation

(redirected from Echo canceller)

echo cancellation

A process which removes unwanted echoes from the signal on a telephone line. Echoes are usually caused by impedance mismatches along an analogue line.

echo cancellation

The elimination of an echo in a two-way voice transmission. Echo is created in the telephone company's central office switch when two-wire lines from the customer are converted to four-wire lines for backbone trunks. The echo is exacerbated over longer distances and by certain kinds of network equipment. A delay of 30ms or more is noticeable, and 50ms is annoying. To eliminate it, the carriers put echo cancellers on their switch ports and in their long-distance trunks at 500 mile intervals.

Using sophisticated DSP circuits that isolate the echo and transmit a reverse frequency to cancel it, echo cancellation is also built into analog modems, speakerphones and quality sound cards. See echo suppression and noise cancellation.
References in periodicals archive ?
India, April 21 -- Echo Canceller Compliance Testing
Server Side Echo canceller (AEC) - your voice will never be echoed back at you.
TELECOMWORLDWIRE-17 May 2007-TI's Telinnovation echo canceller solution deployed across DSP platforms(C)1994-2007 M2 COMMUNICATIONS LTD http://www.
GL Communications has introduced its new and enhanced echo canceller testing tools, which were designed to enable communications carriers and equipment manufacturers to improve the voice quality of wireline and wireless networks.
While competitors require their customers to purchase individual daughter-boards costing several hundred dollars to provide voice enhancement capabilities, Ditech's VQoS software comes bundled as part of the standard Ditech echo canceller.
Expanded Product Line Includes New Telephony Interface Cards and High Performance Software Based Echo Canceller
announced today the release of its new product Acoustic Echo Canceller (AEC) Compliance Test Software.
The design of the new echo canceller reduces the cost per channel compared to the previous echo cancellation products that it replaces and enables wireless networks to support high-quality, high-speed wireless broadband services, Lucent said.
The echo canceller is designed to cancel acoustic feedback between a loud-speaker and a microphone in loud-speaker audio systems and voice-controlled systems.
Also, a new version of the VERITY 3300 echo canceller system has been released with a new electrical interface allowing in-line echo cancellation and more powerful multimedia platforms.
729AB, and a range of other codecs, Network Line Echo Canceller, various tones detection and generation, other telephony components, Fax and Data Modems, and a suite of software utilities simplifying the application development.
TELECOMWORLDWIRE-30 August 2000-Mitel introduces voice echo canceller (C)1994-2000 M2 COMMUNICATIONS LTD http://www.