Residual echo signal in critically sampled subband acoustic echo cancellers based on IIR and FIR filter banks

Abstract

Abstract-The residual echo signal characteristics of critically sampled subband acoustic echo cancellers are analyzed. For finite impulse response (FIR) filter banks, the residual echo signal usually has a relatively broad spectral nature around the subband edges. The residual echo signal of power symmetric infinite impulse response (PS-IIR) filter banks, on the other hand, has very narrowband spectral components around the subband edges. These components can be efficiently removed with PS-IIR notch filters that integrate neatly into the filter banks without introducing perceptually noticeable degradation to the near-end speech. This solution has very low computational complexity and does not impinge on the system performance. Simulation studies with recordings from the cockpit of a car, based on a fast QR least-squares adaptive algorithm, demonstrate the potential of this approach for a practical AEC system.

Design of near perfect reconstruction oversampled filter banks for subband adaptive filters

“…The performance criterion to be minimized by the algorithm is a combination of the filter bank reconstruction error 1 and the stopband energy 2 of the analysis filters h l (k) = 1 + 1 2 (8) where is a positive weighting factor which trades off between the importance of the reconstruction error and the stopband attenuation. In the following, we discuss separately formulations for both 1 and 2 ; and finally, present the design algorithm in Section III-C.…”

“…Thus, multichannel adaptive algorithms are being used in the subbands which exhibit a higher computational complexity and a slower convergence for correlated input signals. If the perfect reconstruction condition is dropped, critically sampled structures are obtainable, which do not need crossadaptive filters, as spectral gaps ensure that aliasing in the subbands does not occur [7], [8]. This spectral loss however prohibits exact system identification and can significantly distort signals passing through the filter bank.…”

Long-term auto-correlation statistics based voice activity detection for strong noisy speech

“…V AD is an important frontend in many speech-related applications, such as mobile communication system [1], echo cancellation [2], speech enhancement [3], speech coding [4], automatic speech recognition [5], etc. The accuracy of V AD is quite critical to the overall performance of those applications.…”

Energy-efficient Hardware Architecture and VLSI Implementation of a Polyphase Channelizer with Applications to Subband Adaptive Filtering

“…with very long impulse response and/or suffer from slow convergence speed [1][2][3][4][5][6]. In such applications, subband adaptive filtering is a viable alternative to conventional least-mean-square (LMS) algorithm since it reduces computational complexity and offers improved convergence rate.…”

“…2, when critical sampling is employed (i.e., N=M), the presence of aliasing requires the use of adaptive cross-filters between adjacent subbands [1] or gap filterbanks [4]. However, systems with cross-filters generally converge more slowly and have higher computation cost, while the distortion produced by gap filter banks may not be acceptable.…”