Title:
ADAPTIVE UNKNOWN SYSTEM OUTPUT ESTIMATE METHOD
Document Type and Number:
Japanese Patent JP3147207
Kind Code:
B2
Abstract:
PURPOSE: To estimate an unknown system output with less calculation quantity by stopping update of an intermediate variable when noise is higher in the level than an echo signal in an echo canceller employing the high speed map method.
CONSTITUTION: In the echo canceller employing the high speed map method, a β reset section 61 is inserted in series between a β calculation section 22 and an (s) update section 30, and the β reset section 61 sets the β to zero with an update stop signal from an update stop discrimination section 51. That is, an autocorrelation section 21 calculates autocorrelation coefficients ri, j(k) of an input signal x(k), the signal x(k) and an intermediate variable z(k) are subject to convolution calculation 32, a multiplier 33 is used to obtain a sum of inner product between a smoothed pre-filter coefficient si(k) and the autocorrelation coefficient roi (k) thereby calculating an output estimate value y436F(k) of an unknown system 15. An estimate error r(k) is calculated from the difference between the estimate value and an output of a receiver thereby calculating a filter coefficient β(k). In the case that the noise level is higher than the echo signal and a variable update stop signal is in existence, β=D is set and an output of the unknown system is estimated with less calculation quantity.
Inventors:
Masafumi Tanaka
Youichi Haneda
Shoji Makino
Youichi Haneda
Shoji Makino
Application Number:
JP10241894A
Publication Date:
March 19, 2001
Filing Date:
May 17, 1994
Export Citation:
Assignee:
Nippon Telegraph and Telephone Corporation
International Classes:
H03H21/00; H04B3/23; (IPC1-7): H03H21/00; H04B3/23
Domestic Patent References:
| JP3226026A | ||||
| JP613940A |
Other References:
１９９０年電子情報通信学会春季全国大会講演論文集［分冊３］（１９９０−３−１８〜２１）ｐ．３−３２２
ＩＥＩＥＣ Ｔｒａｎｓａｃｔｉｏｎｓ ｏｎ Ｆｕｎｄａｍｅｎｔａｌｓ ｏｆ Ｅｌｅｃｔｒｏｎｉｃｓ，Ｃｏｍｍｕｎｉｃａｔｉｏｎｓ ａｎｄ Ｃｏｍｐｕｔｅｒ Ｓｃｉｅｎｃｅｓ Ｅ７８−Ａ［１０］（１９９５−１０）ｐ．１３５５−１３６１
ＩＥＩＥＣ Ｔｒａｎｓａｃｔｉｏｎｓ ｏｎ Ｆｕｎｄａｍｅｎｔａｌｓ ｏｆ Ｅｌｅｃｔｒｏｎｉｃｓ，Ｃｏｍｍｕｎｉｃａｔｉｏｎｓ ａｎｄ Ｃｏｍｐｕｔｅｒ Ｓｃｉｅｎｃｅｓ Ｅ７８−Ａ［１０］（１９９５−１０）ｐ．１３５５−１３６１
Attorney, Agent or Firm:
Suguru Kusano