A Subband Echo Cancellation Method with Pinch and Variable Step Size

Abstract

A kind of sub-band echo cancellation method with contraction variable step length, its steps are: A, sampling and processing of signal, input vector U (n) is divided into I far sub-band vector U through analysis filter one i (n), the near-end signal d(n) picked up by the near-end microphone is divided into I near-terminal band signals d through the analysis filter i (n); the far-end input subband vector U i (n) carry out I extraction through extractor; Obtain far-end input sub-band extraction vector U i (k); Similarly, also for the near terminal with signal d i (n) I extraction is performed by the extractor to obtain the near-terminal strip extraction signal d i (k), B, the output of the filter, the far-end input sub-band extraction vector U i (k) Obtain the output subband signal y by the subband filter in the adaptive echo cancellation filter i (k), C, echo cancellation, D, the update of the weight coefficient vector, based on the square estimator of the denoising near-end signal, the update step size μ of the weight coefficient vector of the sub-band filter is obtained i (k), E, ​​let k=k+1, repeat the steps of A, B, C, D until the end of the call. This method can obtain faster convergence speed and lower steady-state error.

Description

technical field [0001] The invention belongs to the technical field of adaptive echo cancellation for voice communication. Background technique [0002] At present, the echo canceller estimates the echo through the core component—adaptive filter, and subtracts the estimated value of the echo from the near-end signal to achieve the effect of echo cancellation. Adaptive echo cancellation technology has been unanimously recognized because of its low cost and good effect, and it is also one of the most promising echo cancellation technologies recognized internationally. [0003] From the basic principle of echo cancellation, the use of acoustic echo canceller to achieve echo cancellation, the core part of which is the adaptive filter. The least mean square (LMS) algorithm, which is most commonly used in adaptive systems, often cannot achieve good results in echo cancellation applications. For this reason, in order to solve this difficulty, the method of normalized sub-band ada...

AI Technical Summary

Problems solved by technology

In the current adaptive echo cancellation application, the more mature subband method is the adaptive filtering algorithm of the normalized subband class, such as the literature 1 "Variableregularization parameter sign subband adaptive filter" (J.Ni and F.Li, Electron.Lett., vol.46, no.24, pp.1605–1607, Nov.2010.)'s (SSAF) method, which is to add the symbolic subband (SSAF) algorithm to the variable regularization parameter strategy to reduce the fixed The influence of the step size on the convergence speed and steady-state error, this method is the step size of the skip line, the step size change is only related to time, the longer the time, the smaller the step size; therefore, when the application conditions change or the application In the case of unstable conditions, the performance of the algorithm will decrease

Images