Title:
時間領域エコー消去処理においてトーンの存在に起因する誤集束を回避するためのシステムおよび方法
Document Type and Number:
Japanese Patent JP3652705
Kind Code:
B2
Abstract:
A system and method for detecting convergence in an echo canceller prevent false convergence from occurring as a result of receiving only tones in an input signal. An adaptive filter is used in an echo canceller to estimate an echo signal produced by an unknown echo channel. The estimated echo signal is subtracted from the return signal to remove the echo produced by the unknown echo channel. To prevent the echo canceller from falsely converging on a signal which contains only tones a system and method are provided for detecting the presence of tones in the absence of other frequencies. Filter taps of the adaptive filter are filtered to produce a filtered signal. The amount of energy in the filtered signal is compared to the amount of energy in the unfiltered filter taps to determine whether only tones have been present. If only tones have been present, the echo canceller is not allowed to reduce the adaptation step size of the adaptive filter.
Inventors:
Sea, Gilbert Sea
Application Number:
JP53667696A
Publication Date:
May 25, 2005
Filing Date:
May 31, 1996
Export Citation:
Assignee:
QUALCOMM INCORPORATED
International Classes:
H03H21/00; H04B3/23; H04M1/00; H04Q3/42; (IPC1-7): H04B3/23; H03H21/00; H04Q3/42
Domestic Patent References:
| JP481133A | ||||
| JP6335037A | ||||
| JP555960A | ||||
| JP58500229A |
Attorney, Agent or Firm:
Takehiko Suzue
Sadao Muramatsu
Ryo Hashimoto
Toshio Shirane
Sadao Muramatsu
Ryo Hashimoto
Toshio Shirane