| 基于多相滤波器组的非线性回声抵消 |
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| 引用本文： | 梁萌,付中华.基于多相滤波器组的非线性回声抵消[J].信号处理,2020,36(6):921-931. |
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| 作者姓名： | 梁萌 付中华 |
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| 作者单位： | 西北工业大学计算机学院 |
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| 基金项目： | 国家重点研发计划基金(2017YFB1002102) |
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| 摘 要： | 在免提通话系统和移动通信设备中,扬声器常常工作在较高的音量下,容易发生过载现象,从而产生明显的非线性声学回声,这在小微型扬声器中更加常见。常用的线性AEC(Acoustic Echo Cancellation)算法无法消除此类非线性回声,因此通话质量受到严重影响。非线性回声主要表现为额外的高频谐波分量,这些分量使得全带系统不再满足线性关系,而通常的AEC算法都是基于最小化全带误差推导而来,因此性能很容易受到非线性失真的影响。本文提出了一种基于多相滤波器组的子带AEC算法,把全带误差变成了各个子带的误差,因而把谐波失真成分变成了某些子带内的加性噪声,这使得谐波失真较小的那些子带依然能够正常收敛。通过仿真和实测实验,当出现非线性失真时,新方法的ERLE(Echo Return Loss Enhancement)明显高于经典的全带时域和频域方法,对于非线性失真明显的语音信号,ERLE提升约10 dB。
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| 关 键 词： | 回声抵消 非线性回声抵消 多相滤波器组 子带回声抵消算法 扬声器非线性失真 |
| 收稿时间： | 2020-03-05 |
Nonlinear Echo Cancellation Based on Polyphase Filter Bank |
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| Liang Meng,Fu Zhonghua.Nonlinear Echo Cancellation Based on Polyphase Filter Bank[J].Signal Processing,2020,36(6):921-931. |
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| Authors: | Liang Meng Fu Zhonghua |
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| Affiliation: | School of Computer Science,Northwestern Polytechnical University |
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| Abstract: | In hand-free telephone systems and mobile communication devices, the loudspeakers often work with large volume and are easily in overload status, so obvious nonlinear acoustic echo occurs. This phenomenon is more usual in devices with small- or micro-loudspeakers. The general AEC (Acoustic Echo Cancellation) algorithm cannot cancel the nonlinear echo, thus the communication speech quality degrades significantly. The nonlinear echo has many extra high-frequency harmonic distortions, and these distortions break the linear constraint of a full-band adaptive filter algorithm. Since the general AEC algorithms are derived to minimize the full-band error, their performances are very sensitive to the nonlinear distortion. This paper proposes a subband AEC algorithms based on polyphase filter-bank, which transforms the fullband error into subband errors, and those harmonic distortions become additive noise in corresponding subbands. In those bands that distortions are small, the subband adaptive filter can convergence normally. In simulation and real tests, the results show that when the nonlinear distortion occurs, the proposed method achieves significantly better ERLE (Echo Return Loss Enhancement) than the typical time-domain and frequency-domain methods. For speech signals with obvious nonlinear distortion, ERLE improves about 10 dB. |
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| Keywords: | echo cancellation nonlinear echo cancellation polyphase filter bank subband acoustic echo cancellation algorithm loudspeaker nonlinear distortion |
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