Top of page

Font Size

Content Area

Technology for an Echo Canceller that Works in a Varied Sound Environment

- An echo canceller that works in a variety of hands-free speech environments -


Advances in the broadband world are expanding opportunities to use hands-free communication in a variety of environments. However, problems can arise in environments that are not designed for teleconferencing. This technology makes possible good hands-free communication by addressing two problems that arise when a video phone is used in a residential home: difficulty in understanding the other partyís speech and signal delay.


  • Even when the surroundings become noisy, this technology makes the other partyís speech easy to understand by adjusting the frequency characteristics of the speakerís voice to the spectrum of the ambient noise.
  • Digital TVs add some delay time to external input signals, and this delay time varies from one home TV set to another. This technology unifies this delay time so that the echo canceller can work correctly, irrespective of the devices to which it is connected.

[image] Technology for an Echo Canceller that Works in a Varied Sound Environment

Application fields

  • Audio conferencing services
  • Videophone/videoconferencing services
  • Hands-free devices
  • Mobile devices


  • This technology eliminates device dependence, a feature not available in technologies available on the market.
  • Unlike automatic gain control, this technology can increase the volume of sound produced while suppressing howling.
Footer Area
Copyright © 2010 Nippon Telegraph and Telephone Corporation