共查询到20条相似文献,搜索用时 78 毫秒
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ZHAO Xiao-hui ZHAO YueLaboratory of Information Science College of Communication Engineering Jilin University Changchun China 《中国邮电高校学报(英文版)》2005,12(3)
1 Introduction In speech communication applications ,the presence ofcoupling fromloudspeaker to the microphone often re-sults in undesired acoustic echo that seriously degradesspeech quality.Current solutions for removingthis echoare based on the real ti me identification of the acoustici mpulse response by using adaptive filtering or AdaptiveEcho Cancellation (AEC) filter techniques . Several AEC algorithms have been proposed for thisproblem. An acoustic echo canceller based upon inputort… 相似文献
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Tools are presented which enable the practitioner to efficiently design all-pass based, highly selective low-pass power symmetric-infinite impulse response (PS-IIR) filters which are well suited for sub-band decomposition in applications such as multirate acoustic echo cancellation (MAEC) 相似文献
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针对稀疏信道条件下的网络回声抵消问题。提出了一种比例归一化子带自适应滤波算法。该算法基于子带分解结构,并利用网络中回声路径的稀疏特性,使得各个系数的步长与该系数的绝对值成比例,加快了活动系数的收敛速度,从而改善了子带分解算法在稀疏信道条件下的性能。仿真结果表明:将所提算法应用于网络回声消除器,能够获得很快的收敛速度和很低的稳态失调。 相似文献
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An acoustic echo canceller with sub-band noise cancelling that employs a cascade configuration is proposed. The adaptation control adopted to match the occurrence of intermittent speech/echo and continuous room noise using the NLMS algorithm is very effective in echo and noise cancellation. Hardware is implemented and its performance evaluated through experiments. The noise cancellation significantly enhances overall echo-cancellation performance.<> 相似文献
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The acoustic echo cancellation with large adaptive filters is a computationally intensive problem and needs real time cost effective solution. To deal with these challenges, designers have increasingly turned to mixed Hardware/Software (HW/SW) implementation of echo canceller algorithms. This paper presents a co-design methodology and environment for both hardware and software modules. We describe how High Level Synthesis (HLS) tools like GAUT and SYNDEX can be efficiently used for rapid prototyping of heterogeneous architecture based on DSP TMS320C40 and ASIC. The HW/SW interface synthesis task is especially discussed since it constitutes a key issue of the whole design. As an illustration, we present a mixed implementation of the GMDF alpha algorithm, an adaptive filter well suited to acoustic echo cancellation, on both ASIC and TMS320C40 DSP. 相似文献
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A novel algorithm specifically for use in stereophonic acoustic echo cancellation (SAEC) environments is introduced. It is based on an alternating fixed-point (FP) structure. Analysis provides bounds to ensure that the algorithm has the form of a contraction mapping (CM). Simulation results show improved performance over algorithms with similar computational complexity in the presence of noise 相似文献
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《Circuits and Systems II: Express Briefs, IEEE Transactions on》2008,55(10):1056-1060
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Hands-free terminals for speech communication employ adaptive filters to reduce echoes resulting from the acoustic coupling between loudspeaker and microphone. When using a personal computer with commercial audio hardware for teleconferencing, a sampling frequency offset between the loudspeaker output D/A converter and the microphone input A/D converter often occurs. In this case, state-of-the-art echo cancellation algorithms fail to track the correct room impulse response. In this paper, we present a novel least mean square (LMS-type) adaptive algorithm to estimate the frequency offset and resynchronize the signals using arbitrary sampling rate conversion. In conjunction with a normalized LMS-type adaptive filter for room impulse response tracking, the proposed system widely removes the deteriorating effects of a frequency offset up to several Hz and restores the functionality of echo cancellation. 相似文献
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Design and performance of adaptive systems based on structured stochastic optimization strategies 总被引:2,自引:0,他引:2
The theory and design of linear adaptive filters based on FIR filter structures is well developed and widely applied in practice. However, the same is not true for more general classes of adaptive systems such as linear infinite impulse response adaptive filters (MR) and nonlinear adaptive systems. This situation results because both linear IIR structures and nonlinear structures tend to produce multi-modal error surfaces for which stochastic gradient optimization strategies may fail to reach the global minimum. After briefly discussing the state of the art in linear adaptive filtering, the attention of this paper is turned to MR and nonlinear adaptive systems for potential use in echo cancellation, channel equalization, acoustic channel modeling, nonlinear prediction, and nonlinear system identification. Structured stochastic optimization algorithms that are effective on multimodal error surfaces are then introduced, with particular attention to the particle swarm optimization (PSO) technique. The PSO algorithm is demonstrated on some representative IIR and nonlinear filter structures, and both performance and computational complexity are analyzed for these types of nonlinear systems. 相似文献
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Some adaptive signal processing applications, such as wideband active noise control and acoustic echo cancellation, involve adaptive filters with hundreds of taps. The computational burden associated with these long adaptive filters precludes their use for many low-cost applications. In addition, adaptive filters with many taps may also suffer from slow convergence, especially if the reference signal spectrum has a large dynamic range. Subband techniques have been previously developed for adaptive filters to solve these problems. However, the conventional approach is ruled out for many applications because delay is introduced into the signal path. The paper presents a new type of subband adaptive filter architecture in which the adaptive weights are computed in subbands, but collectively transformed into an equivalent set of wideband filter coefficients. In this manner, signal path delay is avoided while retaining the computational and convergence speed advantages of subband processing. An additional benefit accrues through a significant reduction of aliasing effects. An example of the general technique is presented for a 32-subband design using a polyphase FFT implementation. For this example, the number of multiplies required are only about one-third that of a conventional full band design with zero delay, and only slightly greater than that of a conventional subband design with 16 ms delay 相似文献
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Lindstrom F. Schuldt C. Langstrom M. Claesson I. 《IEEE transactions on circuits and systems. I, Regular papers》2007,54(9):2011-2018
The two-path algorithm is an adaptive filter algorithm based on a parallel filter structure, which has been found to be useful for line echo cancellation as well as for acoustic echo cancellation. It is well known that in finite precision arithmetic, the adaptation process of adaptive algorithms can be reduced or even halted due to finite precision effects. This paper proposes a variant of the two-path scheme where the effects of quantization are reduced, without any significant increase in complexity. The improvement is shown by simulations using bandlimited flat spectrum noise as well as real speech signals. 相似文献
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Breining C. Dreiscitel P. Hansler E. Mader A. Nitsch B. Puder H. Schertler T. Schmidt G. Tilp J. 《Signal Processing Magazine, IEEE》1999,16(4):42-69
We have discussed the application of high-order adaptive filters to the problem of acoustical echo cancellation with particular application to hands free telephone systems. We described a means to achieve robust performance. We further presented methods for reducing computational complexity that allow implementation in low-cost, fixed-point digital signal processors. Progress in technology will allow the use of more sophisticated algorithms at lower cost in the near future 相似文献
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针对短波电台入网中对皮抵消的要求,本文提出采用基于LS准则的FTF算法,同时把“稳健估计(RE)”应用于FTF算法中,并设计出一种新的自适应回波抵消器结构,理论分析和计算机模拟结果都表明该回波抵消器具有收敛速度快,稳态误差小,稳定可靠,抗干扰能力强等特点,明显地提高了短波电台入网的性能。 相似文献
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一种改进的双通道滤波回声抵消算法——过采样无延迟子带方法 总被引:1,自引:1,他引:0
在强相关大动态范围语音作用下,回声抵消器直接更新上千阶自适应滤波器系数,计算量大、收敛速度慢。采用子带分析与合成的方法能够减少计算量和提高算法的收敛性能,但子带的分析与合成也给线路中引入了信号延迟。提出了一种改进的双通道滤波回声抵消算法,将子带自适应滤波器映射到全频带滤波器,减少了信号的延迟;同时采用双通道滤波器。使系统工作在较小残余回声功率下。仿真结果表明,改进算法在单边会话情况下收敛快.具有较好的回声抵消效果。 相似文献
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《Signal Processing, IEEE Transactions on》2008,56(12):5840-5850
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This paper proposes Bayesian Regularization And Nonnegative Deconvolution (BRAND) for accurately and robustly estimating acoustic room impulse responses for applications such as time-delay estimation and echo cancellation. Similar to conventional deconvolution methods, BRAND estimates the coefficients of convolutive finite-impulse-response (FIR) filters using least-square optimization. However, BRAND exploits the nonnegative, sparse structure of acoustic room impulse responses with nonnegativity constraints and L/sub 1/-norm sparsity regularization on the filter coefficients. The optimization problem is modeled within the context of a probabilistic Bayesian framework, and expectation-maximization (EM) is used to derive efficient update rules for estimating the optimal regularization parameters. BRAND is demonstrated on two representative examples, subsample time-delay estimation in reverberant environments and acoustic echo cancellation. The results presented in this paper show the advantages of BRAND in high temporal resolution and robustness to ambient noise compared with other conventional techniques. 相似文献