In this paper, a non-uniform subband adaptive structure with critical sampling of the subband signals is derived. With the assumption of non-overlapping between non-adjacent analysis filters, the resulting structure yields exact modeling of an arbitrary FIR system. An LMS-type adaptation algorithm, which minimizes the sum of the subband squared-errors, is obtained for updating the coefficients ...

The use of hands-free communication in cars, computer applications and video conferencing has created a demand for high-quality acoustic echo cancellation. In these applications the acoustic channel has typically a long impulse response in the order of 100ms. Typical lengths of adaptive FIRfilters can be 500-1500 taps. In order to reduce the complexity and also to improve the convergence rate, ...

We present a new subband affine projection (SAP) algorithm for the adaptive acoustic echo cancellation with long echo path delay. Generally, the acoustic echo canceller suffers from the long echo path and large computational complexity. To solve this problem, the proposed algorithm combines merits of the affine projection (AP) algorithm and the subband filtering. Convergence speed of the propos...

Frequency-domain and subband implementations improve the computational efficiency and the convergence rate of adaptive schemes. The well-known multidelay adaptive filter (MDF) belongs to this class of block adaptive structures and is a DFT-based algorithm. In this paper, we develop adaptive structures that are based on the trigonometric transforms DCT and DST and on the discrete Hartley transfo...

This paper evaluates the performance of various biorthogonal filters using adaptive synthesis filter banks for image compression. The adaptive synthesis filter banks are used to exploit the phase diversity of synthesis filters in subband coding system. Odd length biorthogonal filters are used because even length filters exhibit fractional delay in compression. It is shown that adaptive synthesi...

This thesis investigates broadband adaptive beamforming for signal targets located in the near field of an array. The primary application of this research is hands-free sound pickup and speech enhancement for wideband telephony. The technical challenges are three-fold. Broadband beamformers are difficult to design due to large frequency dependent beampattern variations and reduced performances ...