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.

Near Perfect Reconstruction Filter Banks for Power Quality Analysis

Abstract: The wavelet transform has been successfully used in the area of power quality analysis. There are many published papers with methods for power quality disturbance classification or harmonics measurement, which use wavelet transform. However, the properties of the wavelet transform can drastically vary from the choice of the wavelet. In this paper we analyze the influence of the choice of the wavelet to the accuracy of the power quality classification method and to high frequency harmonics measurements. Additionally to the well known wavelet filters we introduce near perfect reconstruction filter banks. The simulation results indicate that these filter banks are a good choice for classification of power quality disturbances, especially in the presence of noise and for high frequency harmonics measurements.

Complementary sets of sequences: a filter bank approach

Abstract: The relationship between orthogonal finite impulse response filter bank structures, and orthonormal bases of compactly supported wavelets is a well-developed theory. In this paper, we identify further relationships between the design and construction of complementary pairs of sequences, filter banks satisfying the condition for perfect reconstruction and the property of losslessness. We then develop a construction method which enables a new class of complementary sequences to be formulated. Finally, we generalise these new sequences to form complementary sets, thus increasing the number of possible application areas for this class of sequences.

Information-theoretic performance of quadrature mirror filters

Abstract: Most existing quadrature mirror filters (QMFs) closely match the derived closed-form expression for an efficient class of QMFs. We use the closed-form expressions to derive the relationship between information-theoretic loss and the frequency selectivity of the QMF, by calculating first-order entropy as well as rate-distortion theoretic performance of a two band QMF system. We find that practical QMFs do not suffer a significant information-theoretic loss with first-order autoregressive Gaussian sources. With second-order autoregressive sources we find that practical QMFs suffer a notable information-theoretic loss when the bandwidth of the source is extremely narrow, but incur a small loss when the bandwidth is wider. We suggest that our results broadly apply to higher order autoregressive sources as well.

A general design of mixed IIR-FIR two channel QMF bank

Abstract: A general family of mixed IIR/FIR two-channel QMF filter banks with near perfect reconstruction (NPR) is presented. The design method is general in the sense that all possible distortions (aliasing, imaging, amplitude and phase distorsions) can be simultaneously and arbitrarily minimized. The method is based on a simple algorithm, also included, to approximate unstable all-pole filters with FIR filters. The resulting filter bank is efficient because a polyphase implementation is possible and delay is low compared to conventional FIR filter banks. It is also shown that some well-known two-channel FIR and IIR filter banks are particular classes of the proposed one. Examples are also included.

A simple method for designing pseudo QMF banks

Abstract: The traditional designs for the prototype filter of M-band pseudo quadrature mirror filter (QMF) banks usually involve nonlinear optimization. A simple design approach that involves the optimization of only a single parameter is presented. In this method, the prototype filter is formulated as an interpolated FIR filter and is indirectly designed by varying the passband edge of the model filter. A design example is presented to show that very good design can be obtained in spite of the limit of the formulation.