Topic
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.
Papers published on a yearly basis
Papers
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04 Mar 1999TL;DR: In this paper, a radio-frequency signal receive section, including an antenna, collectively receives radiofrequency signals on a plurality of channels each of which is modulated with data and outputs a received signal.
Abstract: A radio-frequency signal receive section, including an antenna, collectively receives radio-frequency signals on a plurality of channels each of which is modulated with data and outputs a received signal. In a quadrature demodulator, the received signal is multiplied by each of first quadrature local signals to produce quadrature baseband signals. In two low-pass filters, low-frequency component signals are extracted from the quadrature baseband signals. In a quadrature modulator, the low-frequency component signals are multiplied by second quadrature local signals and thereby converted into quadrature intermediate-frequency signals, which are in turn combined into an output signal. After converted into a digital signal, the output signal of the quadrature modulator is inputted to a digital signal processing unit where a signal on at least one channel is selected and the selected signal is processed to recover the original data.
46 citations
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TL;DR: It is shown that the texture energy method can be understood as the equivalent of an envelope detector receiver commonly used in AM communication techniques and a further linear relationship between the local variances of the filter outputs and the autocorrelation function of the texture process is derived.
44 citations
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29 Oct 1993
TL;DR: In this paper, a wavelet transform (quadrature mirror filter pyramid) is used to decompose an image into bands containing information from different scales (spatial frequencies) and orientations, and conditional probabilities between these different scale bands are then determined, and used as the basis for a predictive coder.
Abstract: A technique for image compression is based on a very simple type of iterative fractal. A wavelet transform (quadrature mirror filter pyramid) is used to decompose an image into bands containing information from different scales (spatial frequencies) and orientations. The conditional probabilities between these different scale bands are then determined, and used as the basis for a predictive coder. The wavelet transform's various scale and orientation bands have a great deal of redundant, self-similar structure in the form of multi-modal conditional probabilities, so that linear predictors perform poorly. A simple histogram method is used to determine the multi-modal conditional probabilities between scales. The resulting predictive coder is easily integrated into existing subband coding schemes. >
44 citations
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TL;DR: A modified filled function method is proposed for finding the global minimum of the nonconvex optimization problem for a two-channel linear phase finite-impulse-response quadrature mirror filter bank minimax design problem.
Abstract: In this correspondence, a two-channel linear phase finite-impulse-response (FIR) quadrature mirror filter (QMF) bank minimax design problem is formulated as a nonconvex optimization problem so that a weighted sum of the maximum amplitude distortion of the filter bank, the maximum passband ripple magnitude and the maximum stopband ripple magnitude of the prototype filter is minimized subject to specifications on these performances. A modified filled function method is proposed for finding the global minimum of the nonconvex optimization problem. Computer numerical simulations show that our proposed design method is efficient and effective.
43 citations
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TL;DR: In this article, the authors describe a perfect-reconstruction two-channel QMF (quadrature mirror filter) bank, in which the analysis and synthesis filters have linear phases.
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.<>
42 citations