Title:
ECHO CANCELER
Document Type and Number:
Japanese Patent JP3241328
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To accurately specify an initial delay quantity variable with environment, etc., and to reduce a calculation quantity and a memory.
SOLUTION: This echo canceler for canceling echoes by using adaptive algorithm is provided with an adaptive filter part 102 which composes a dummy echo by analyzing characteristics of an echo path, an initial operation control part 108 which controls initial operation when the states of a far-end input and a near-end input match set standards (when the mean power of the near-end input and far-end input is less and larger than a certain threshold), and a coefficient update quantity decision part which finds the tap coefficient indicating the largest update quantity by evaluating the time mean of update quantities by tap coefficients and decides that the section before the tap coefficient is an initial delay. Here, a decision may be made on the basis of a found section where the time mean of the sums of squares of every arbitrary number of update quantities of tap coefficients varies.
Inventors:
Yoshihiro Ariyama
Application Number:
JP27708998A
Publication Date:
December 25, 2001
Filing Date:
September 30, 1998
Export Citation:
Assignee:
Oki Electric Industry Co., Ltd.
International Classes:
H03H17/02; H04B3/23; H04M9/08; H03H21/00; (IPC1-7): H04B3/23; H03H17/02; H03H21/00
Domestic Patent References:
| JP9233003A | ||||
| JP8125593A | ||||
| JP7202766A | ||||
| JP786993A | ||||
| JP6237147A | ||||
| JP4245810A | ||||
| JP4234212A |
Attorney, Agent or Firm:
Nobuyuki Kudo
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