Abstract: An interactive subscriber telephone terminal, comprising: a display screen; a plurality of temporarily definable response/data entry keys; and local control means for selectively causing the display screen and/or the response/data entry keys to be controlled by one of: remote signals transmitted to the terminal from a telephone switching office, and the local control means.
Type:
Grant
Filed:
December 6, 1997
Date of Patent:
May 16, 2000
Assignee:
Northern Telecom Limited
Inventors:
William V. Pezzullo, Michel J. Brisebois, Joseph B. Johns, Kenneth M. Orford, Kristin J. Travis, Bruce H. Tsuji, William T. Ross, Andre J. Robert, Clifford D. Read
Abstract: Transmission system comprising a sub-band echo canceller which includes a sub-band coding arrangement.The invention relates to a transmission system comprising a sub-band echo canceller which includes a canceller that can be switched between a receive path (r) and a send path (s).To reduce the computational complexity as well as the signal delays also with sub-band coding or sub-band decoding, the sub-band coding arrangement comprises a synthesis filter bank and an analysis filter bank which are provided for sub-band coding and also for sub-band echo cancellation.Advantageous applications for the echo canceller are subscriber terminal units, for example, hands-free facilities for car telephones, videophones or video conference units which have an echo path formed by at least one microphone and at least one loudspeaker.