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.

An approximation of Daubechies wavelet matrices by perfect reconstruction filter banks with rational coefficients

Abstract: It is described how the coefficients of Daubechies wavelet matrices can be approximated by rational numbers in such a way that the perfect reconstruction property of the filter bank be preserved exactly.

Perfect reconstructional multidimensional filter banks with time-varying basis functions

Abstract: Many multidimensional signals of interest are nonstationary and thus have statistical characteristics that change temporally and/or spatially. It is reasonable to expect that time-varying transforms can better model M-D signals than time-invariant ones. We discuss time-varying multidimensional filter banks with adaptive filter coefficients. The focus is on the design of exact reconstructing multidimensional adaptive filter banks. We extend our 1-D time-varying filter bank design method to multiple dimensions to consider the design of perfect reconstructing time-varying nonseparable filter banks. The resulting design method is simple, elegant and extremely powerful. >

Error compensator for converting high frequency signals to base band feeds digitized signals of in-phase, quadrature branches to 2-channel adaptive filter, injects test signal during signal pauses

Abstract: The arrangement digitizes the HF signal or a derived IF signal after separation into in-phase and quadrature components. The digitized signals of the in-phase and quadrature branches are fed to a two-channel adaptive filter (20) and a test signal (5) is fed in before signal separation during signal pauses in which there is no signal for conversion.

A family of wavelets which are dilatable by simple IIR filters (EEG analysis)

Abstract: The family of wavelets called neural wavelets has zero mean, spectral peak at a frequency varies as square root n and 20 n dB/decade rolloff where n is the order of the wavelet. The effective duration shortens with increasing n for a given t/sub 0/, where the parameter t/sub 0/ allows time scaling of the wavelets. A simple infinite impulse response (IIR) filter is developed which expands or contracts the wavelet and can be designed to change the order n. The filter is used to detect partially overlapping constituent wavelets of a composite waveform. Filter design and noise sensitivity are discussed. >

Multirate Filter Bank-based Conversion of Image Resolution

Abstract: This paper proposes a multirate processing scheme for the conversion of image resolution by using filter banks. A resolution-converted signal is synthesized from decomposed ones by the filter banks. A new design of filter banks for resolution conversion is proposed. The design strategy is that we make the output of synthesis filter banks nearly equal to the one of a direct resolution conversion approach. Simulation results are also given, in which we examine the performance of the proposed synthesis scheme.