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
More filters
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06 Aug 2001TL;DR: A novel algorithm is proposed that minimizes a more realistic hardware cost, such as adder cells, subject to a prescribed output accuracy taking account of rounding and overflow effects, instead of using just the SOPOT terms as in conventional methods.
Abstract: This paper proposes a novel algorithm for the design and hardware reduction of a class of multiplier-less two-channel perfect reconstruction (PR) filter banks (FB) using sum-of-powers-of-two (SOPOT) coefficients. It minimizes a more realistic hardware cost, such as adder cells, subject to a prescribed output accuracy taking account of rounding and overflow effects, instead of using just the SOPOT terms as in conventional methods. Furthermore, by using multiplier blocks (MB) to implement the filters in the FBs, significant overall saving in hardware resources can be achieved. An effective random search algorithm is also proposed to solve the design problem, which is also applicable to PR IIR FBs with highly nonlinear objective functions. Perfect reconstruction multirate filter have important applications in signal analysis, signal coding and the design of wavelet bases.
13 citations
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TL;DR: Using parametrizations of the prototype filter coefficients, it was found that the optimal filter is the regular Daubechies D/sub 2/ wavelet filter.
Abstract: The optimization of subband filter banks for signal and image coding is normally dealt with by numerical means. It is shown that this optimization can be done analytically in the case of the prototype four-tap causal conjugate quadrature filter (CQF). The coding gain and aliasing energy are considered in the optimization. Using parametrizations of the prototype filter coefficients, it was found that the optimal filter is the regular Daubechies D/sub 2/ wavelet filter.
13 citations
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26 Apr 1985TL;DR: It is found that the Least-Squares (LS) adaptive lattice predictor outperforms both the pole-zero adaptive predictor recommended by CCITT and a first-order fixed predictor and an optimal dynamic bit allocation strategy.
Abstract: In this study it is our goal to improve the performance of ADPCM and subband speech coders at medium bit rates (9.6∼16 kb/s) without increasing the coder complexity substantially. Various major building blocks including the predictors (both fixed and adaptive), subband quadrature mirror filter (QMF) and bit assignment strategy (both static and dynamic) are investigated in detail. We have found that (1) the Least-Squares (LS) adaptive lattice predictor outperforms both the pole-zero adaptive predictor recommended by CCITT and a first-order fixed predictor. (2) more subbands can improve the coder performance (3) longer QMF can reduce the interband aliasing and improve the subjective performance of a subband coder (4) an optimal dynamic bit allocation scheme with an improvement of SNR as high as 5 dB is much more favorable than a fixed bit allocation. With all of the above finding we propose a 4-band hybrid subband coder with an LS adaptive lattice predictor and an optimal dynamic bit allocation strategy.
13 citations
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TL;DR: The effects of filter shaping and nonlinearity in a coherent quadrature phase-shift-keyed (QPSK) system are investigated andumerical results are obtained which describe the effect of different transmitter filter characteristics on system performance.
Abstract: The effects of filter shaping and nonlinearity in a coherent quadrature phase-shift-keyed (QPSK) system are investigated. Optimization of the receiver filter with respect to the meansquare error (MSE) is considered. Optimization is performed under two different constraints, corresponding to implementation of the filter at intermediate frequency and baseband, respectively. As an example a channel with a typical traveling-wave tube (TWT) nonlinearity is studied. Numerical results are obtained which describe the effect of different transmitter filter characteristics on system performance.
13 citations
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05 Mar 2007TL;DR: In this paper, a head related transfer function (HRTF) is applied in a quadrature mirror filter (QMF) domain, thereby generating a 3D stereo signal by using a surround data stream.
Abstract: A method, medium, and system generating a 3-dimensional (3D) stereo signal in a decoder by using a surround data stream. According to such a method, medium, and system, a head related transfer function (HRTF) is applied in a quadrature mirror filter (QMF) domain, thereby generating a 3D stereo signal by using a surround data stream.
13 citations