Title:
【発明の名称】エコーキャンセラーのディスエーブルトーン信号を検出するための方法
Document Type and Number:
Japanese Patent JP3408253
Kind Code:
B2
Abstract:
PCT No. PCT/FI92/00286 Sec. 371 Date Jun. 23, 1993 Sec. 102(e) Date Jun. 23, 1993 PCT Filed Oct. 28, 1992 PCT Pub. No. WO93/09607 PCT Pub. Date May 13, 1993.A disable tone detection method for an echo canceller, in which the disable tone signal is within a predetermined tolerance range from a nominal frequency and includes phase inversions occurring at predetermined intervals. The method includes the steps of a) removing frequencies outside the tolerance range from an input signal (Sin, Rin) by band-pass filtering (33), b) sampling (34) the filtered signal at a sampling frequency, the sampling frequency being about half of the nominal frequency, so as to alise the sample signal to the vicinity of the zero frequency, c) creating a substantially in-phase version of the aliased sample signal component, d) delaying the in-phase version by about 2n sample signal periods, where n is a positive integer, e) detecting (34) a phase inversion in the disable tone signal using an XOR operation executed on the aliased sample signal component and the delayed version thereof.
Inventors:
Redemeki Haemo
Application Number:
JP50818193A
Publication Date:
May 19, 2003
Filing Date:
October 28, 1992
Export Citation:
Assignee:
Nokia Telecommunicacion Osaque Yukichia
International Classes:
H04B3/23; H04B3/20; (IPC1-7): H04B3/20
Domestic Patent References:
| JP60121856A | ||||
| JP59153358A | ||||
| JP4239824A |
Attorney, Agent or Firm:
Minoru Nakamura (6 outside)