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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
More filters
Journal ArticleDOI
TL;DR: Four popular biorthogonal wavelet filter banks are systematically verified to exhibit performance competitive to several state-of-the-art BWFBs for image compression, and yet require lower computational costs.
Abstract: We construct popular biorthogonal wavelet filter banks (BWFBs) having the linear phase and arbitrary multiplicity of vanishing moments (VMs). A novel parametrization construction technique, which is based on the theory of Diophantine equation, is presented and explicit one-parameter expressions of the BWFBs are derived. Using the expressions, any one-parameter family of BWFBs with different VMs can be constructed, and ten families, i.e., 5/7, 6/6, 9/7, 6/10, 5/11, 10/6, 13/7, 6/14, 17/11, and 10/18 families, are constructed here. The free parameter can be used to optimize the resulting BWFBs with respect to other criteria. In particular, in each family, three specific BWFBs with attractive features are obtained by adjusting the free parameter: the first has optimum coding gain and rational coefficients; the second which also has rational coefficients is very close to a quadrature mirror filter (QMF) bank; and the third which has binary coefficients can realize a multiplication-free discrete wavelet transform. In addition, four BWFBs are systematically verified to exhibit performance competitive to several state-of-the-art BWFBs for image compression, and yet require lower computational costs.

16 citations

Journal ArticleDOI
TL;DR: A model-based method is used to analyze the most general time-varying filter bank, where all parameters in the filter bank change with time, including filter length, decimator factor, and the number of channel.
Abstract: In this paper, a model-based method is used to analyze the most general time-varying filter bank, where all parameters in the filter bank change with time, including filter length, decimator factor, and the number of channel. Through modeling the time-varying filter bank at a fixed time point as a time-invariant filter bank, we change the study of the most general time-varying filter bank to study of the established model. Based on the model, the most general time-varying filter bank is analyzed in both polyphase domain and modulation domain. The general perfect reconstruction (PR) conditions of the most general time-varying filter bank are given using time-varying polyphase matrices in the polyphase domain. In the modulation domain, the time-varying distortion-matrix is presented, and the distortion-free condition of the most general time-varying filter bank is given. Based on the established theory for the most general time-varying filter bank, in the second part of this paper, the time-varying cosine-modulated lapped transform (TV-MLT) as an example is analyzed in detail. An interesting design approach called the window-switching technique, used to design the time-varying prototype windows for a perfectly reconstructed TV-MLT, is introduced. The window-switching technique provides us with the possibility to design a perfectly reconstructed TV-MLT without complex mathematical optimization computation, and simply by graphically building the prototype windows in the transition period based on the given diagrams of the prototype windows before and after the transform changing

16 citations

Proceedings ArticleDOI
31 Oct 1994
TL;DR: A simple design method is proposed for nonuniform integer-decimated filter banks (near perfect reconstruction) to transform the non uniform filter bank design problem to a corresponding uniform filterBank design problem.
Abstract: The theory and design of perfect-reconstruction uniform-band QMF banks have been extensively studied. For nonuniform-band filter banks, there is a lack of efficient design methods. We propose a simple design method for nonuniform integer-decimated filter banks (near perfect reconstruction). The approach is to transform the nonuniform filter bank design problem to a corresponding uniform filter bank design problem. Therefore, only one prototype filter needs to be designed. The analysis and synthesis filters are simple combinations of the cosine modulated versions of the prototype filter. An example is given to demonstrate the proposed method. >

16 citations

Patent
01 Dec 2009
TL;DR: In this paper, a digital filter network consisting of a set of filter tap coefficients and configuration means for configuring values of said set of coefficients is used to correct a frequency dependent quadrature error.
Abstract: A transmit chain comprises a correction network (1a) for correcting a frequency dependent quadrature error between in-phase and quadrature signal paths for the transmission of an input signal. The correction network has an in- phase input port, a quadrature input port, an in-phase output port and a quadrature output port and each input port is connected to each output port by a digital filter network, the digital filter network comprising a set of filter tap coefficients and configuration means for configuring values of said set of filter tap coefficients. Input signals are up-converted, and a portion of the up- converted signal is coupled to a quadrature downconverter (21). A controller (22) determines an error signal by comparing the down-converted signal with the input signal and modifies the set of values of filter tap coefficients on the basis of the error signal and the input signal to correct said frequency dependent quadrature error.

16 citations

Patent
12 Jan 2001
TL;DR: In this paper, a radio FM receiver is provided with a receiver portion with quadrature channels for converting received radio frequency signals into center frequency Quadrature signals, a center frequency filter circuit connected to the former for suppressing undesirable image frequencies, and a first quad-ature PLL demodulator for demodulating the obtained center frequency quadratures signals, being tuned to the carrier frequency within the selected frequency band.
Abstract: A radio FM receiver is provided with a receiver portion with quadrature channels for converting received radio frequency signals into center frequency quadrature signals, a center frequency filter circuit connected to the former for suppressing undesirable image frequencies, and a first quadrature PLL demodulator for demodulating the obtained center frequency quadrature signals, said PLL being tuned to the carrier frequency within the selected frequency band. An error detector is furthermore present for detecting amplitude and phase errors in the quadrature channels, which error detector in response to the quadrature components of the center frequency signals, the quadrature signals of a VCO in the quadrature PLL demodulator, and the filtered difference said quadrature components of the center frequency signal, supplies amplitude and phase correction signals to a quadrature channel correction network which is provided between the filter circuit and the quadrature PLL demodulator.

16 citations

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231
20227
20214
20203
20197
201812