Quadrature mirror filter

About: Quadrature mirror filter is a research topic. Over the lifetime, 955 publications have been published within this topic receiving 28900 citations.

How to capture all FIR perfect reconstruction QMF banks with unimodular matrices

Abstract: The problem of perfect reconstruction in maximally decimated FIR (finite impulse response) QMF (quadrature mirror filter) banks is revisited. A necessary and sufficient condition for perfect reconstruction in this system is that the polyphase matrix of the analysis bank must have a determinant equal to a delay. The author explores various avenues to completely parameterize such matrices. It is shown that the problem can always be decomposed into two problems: one of parameterizing lossless matrices, and one of parameterizing unimodular matrices. Several possibilities for unimodular parameterization are explored. >

Low-order IIR filter bank design

Abstract: The advantage of infinite-impulse response (IIR) filters over finite-impulse response (FIR) ones is that the former require a much lower order (much fewer multipliers and adders) to obtain the desired response specifications. However, in contrast with well-developed FIR filter bank design theory, there is no satisfactory methodology for IIR filter bank design. The well-known IIR filters are mostly derived by rather heuristic techniques, which work in only narrow design classes. The existing deterministic techniques usually lead to too high order IIR filters and thus cannot be practically used. In this paper, we propose a new method to solve the low-order IIR filter bank design, which is based on tractable linear-matrix inequality (LMI) optimization. Our focus is the quadrature mirror filter bank design, although other IIR filter related problems can be treated and solved in a similar way. The viability of our theoretical development is confirmed by extensive simulation.

Sub-band coder design incorporating quadrature filters and pitch prediction

Abstract: In this paper we discuss several new issues in the design of sub-band coders for low bit-rate speech coding. We use unequally spaced filter banks to match perceptual criteria for speech. In particular, we apply quadrature mirror filter techniques to provide cancellation of aliasing between sub-bands, thus permitting a reduction in the order of the filters. Preliminary investigations have been made into the use of pitch prediction within the sub-bands. Designs will be discussed for coder bit rates of 9.6 and 16 kb/s and their performance will be compared with earlier sub-band coder designs.

A linear phase two-channel filter bank allowing perfect reconstruction (image coding)

Abstract: Describes a perfect-reconstruction two-channel QMF (quadrature mirror filter) bank, in which the analysis and synthesis filters have linear phases. First, a technique for designing filter banks is presented. Next, the results of two examples demonstrate that the method can lead to good filters although its procedure is very simple; also, this yields filters without multipliers such as the SSKF (symmetric short kernel filter) bank. >

A novel approach to the design of analysis/Synthesis filter banks

Abstract: A novel technique for the design of analysis/synthesis filter banks, such as quadrature-mirror filter (QMF) banks, is presented. The technique is iterative, but each iteration step is mathematically simple. It is based upon a sectional approximation of the filter bank wherein the synthesis section is taken to be known from the previous iteration, and the analysis section is optimized according to the performance criterion. The strategy is then reversed, and the synthesis section optimized. At each iteration, each of these two steps results in an eigenvalue-eigenvector problem of a matrix with dimensionality equal to the number of taps. The technique is exemplified in detail for the QMF bank design problem.