Self adaptive filter and echo offset device

An adaptive filter and echo cancellation technology, which is applied in the field of communication, can solve problems such as slow signal convergence speed, and achieve the effect of accelerating convergence speed and improving performance

CN1859519AInactive Publication Date: 2006-11-08HUAWEI TECH CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2006-11-08
Estimated Expiration
Not applicable · inactive patent

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Abstract

The present invention provides self-adapting filter and echo neutralization unit accomplished utilizing said self-adapting filter, suitable for communication field. Said self-adapting filter is used for outputting simulating echo according to filter and providing compensation to circuit echo. The present invention can speed up self adaptation rate of convergence, improving echo neutralization unit performance without increasing calculated amount and realizing complexity.
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Description

technical field

[0001] The invention belongs to the communication field, and in particular relates to an adaptive filter and an echo canceller realized by using the adaptive filter. Background technique

[0002] In the telephone system, the call quality is often affected by the echo (Echo). Line echo (Line Echo) is one of the main forms. The reason for the line echo is mainly caused by the impedance mismatch of the hybrid conversion coil (Hybrid), which acts as a two-wire and four-wire conversion. Ideally, a hybrid coil will fully transmit the far-end user's signal to the near-end user. However, in actual situations, due to impedance mismatch and other reasons, after the signal from the four-wire side to the second-wire side passes through the hybrid conversion coil, part of the signal will leak back to the four-wire side, and this part of the "leakage" signal will be transmitted back. The far end, so that the far end user can hear his own voice, which is the line echo, s...

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Embodiment Construction

[0053] In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

[0054]In order to further improve the performance of the echo canceller algorithm without increasing too much calculation, the present invention proposes a digital adaptive filter realized by the PAP (Proportionate Affine Projection, proportional affine projection) algorithm, and adopts the Echo canceller implemented by filter.

[0055] The PAP algorithm is an optimization of the AP (Affine Projection, affine projection) algorithm. The following describes the AP algorithm first:

[0056] Let the adaptive filter input vector x(n) be x(n)=[x(n), x(n-1), Λ, x(n-L+1)] T , the coefficient h of the fil...