Title:
【発明の名称】改良型ダブルトーク検出を有するデュアルHアーキテクチャを利用するエコーキャンセラ
Document Type and Number:
Japanese Patent JP2001523926
Kind Code:
A
Abstract:
An echo canceller circuit for use in an echo canceller system is set forth. The echo canceller circuit comprises a first digital filter having non-adaptive tap coefficients to simulate an echo response occurring during a call. A second digital filter having adaptive tap coefficients to simulate an echo response occurring during the call is also used. The adaptive tap coefficients of the second digital filter are updated over the duration of the call. A coefficient transfer controller is disposed in the echo canceller circuit to transfer the adaptive tap coefficients of the second digital filter to replace the tap coefficients of the first digital filter when a value, Ê, is greater than a value, {overscore (E)}, and, concurrently, when Ê is greater than a value, Emax. The value of {overscore (E)} corresponds to the ratio between a signal-plus-echo signal and a first echo compensated signal using the first digital filter. The value of Ê corresponds to the ratio between the signal-plus-echo signal and a second echo compensated signal using the second digital filter. The value of Emax corresponds to the largest Ê experienced over at least a portion of the duration of the call and at which a transfer occurred.
Inventors:
Rubber Tewks, Kenneth Pee.
Yance, Richard C.
Yance, Richard C.
Application Number:
JP2000521640A
Publication Date:
November 27, 2001
Filing Date:
November 13, 1998
Export Citation:
Assignee:
Tellabs Operations, Incorporated
International Classes:
H03H21/00; H04B3/23; H04M1/58; H04M9/08; (IPC1-7): H04B3/23; H03H21/00; H04M1/58; H04M9/08
Attorney, Agent or Firm:
Takashi Ishida (4 others)