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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4 citations
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TL;DR: A more robust technique to design QMFs is proposed, by modifying the frequency domain approach proposed in Lim and Yang with a better initial guess filter obtained by frequency sampling design.
Abstract: It is known that quadrature mirror filters (QMFs) designed using the algorithm in Lim and Yang (1993) suffer from passband anomaly under certain conditions. A modification to this algorithm was proposed in Goh et al. (1996) to overcome this anomaly. However, this design is not a general solution for different stopband edge frequencies. In this paper, we propose a more robust technique to design QMFs, by modifying the frequency domain approach proposed in Lim and Yang with a better initial guess filter obtained by frequency sampling design. The QMF designed employing the proposed technique overcomes the passband anomaly and has excellent frequency response characteristics that are considerably better than those obtained using earlier methods.
4 citations
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01 May 1990TL;DR: A subband adaptive infinite impulse response (IIR) noise cancellation scheme whose structure enables the cancellation of multiple sinusoidal interferences in a received speech signal is presented and it is demonstrated that more than 20-dB signal-to-noise ratio improvements can be achieved.
Abstract: A subband adaptive infinite impulse response (IIR) noise cancellation scheme whose structure enables the cancellation of multiple sinusoidal interferences in a received speech signal is presented. Compared with the classical least mean square adaptive noise cancellation method, this new structure has two major differences. First, the quadrature mirror filter technique is used to decompose signals into subbands. Second, a new constrained adaptive IIR notch filter and adaptive IIR bandpass filter are developed to form an adaptive IIR noise canceller and used to remove the multiple-frequency, or harmonic, noise from a received speech signal. Computer simulations were done using a set of actual speech signals corrupted by car engine noise. Experiments demonstrate that more than 20-dB signal-to-noise ratio improvements can be achieved. >
4 citations
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31 Aug 1998TL;DR: In this paper, a finite impulse response filter including a first circuit for providing plural delayed signals in response to an input signal is presented. And a second circuit is included for multiplying respective ones of the delayed signals by a corresponding coefficient and providing a respective intermediate signal in response thereto.
Abstract: A finite impulse response filter including a first circuit for providing plural delayed signals in response to an input signal. A second circuit is included for multiplying respective ones of the delayed signals by a corresponding coefficient and providing a respective intermediate signal in response thereto. A third circuit selectively changes the sign of respective ones of a first set of the intermediate output signals to provide a set of component in-phase signals. A fourth circuit selectively changes the sign of respective ones of a second set of the intermediate output signals to provide a set of component quadrature signals. The component in-phase signals are combined to provide an in-phase output signal and the component quadrature signals are combined to provide a quadrature output signal. In the illustrative implementation, the coefficients are generated in accordance with an industry standard via a storage device such as a register bank. The third and fourth circuits are controlled by a pseudo-noise sequence generator. The inventive implementation affords a considerable degree of efficiency in design in that in-phase and quadrature filter outputs are generated from a single filter thereby obviating the need for a second filter required by conventional teachings.
4 citations
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10 Dec 2002TL;DR: In this article, a wavelet filter bank was proposed for power transformer inrush currents including high frequency transient effects, where the primary and secondary windings were represented by stages of wavelet filters.
Abstract: This paper presents a model of the power transformer for electromagnetic transient studies, which employs a wavelet filter bank. In this model both the primary and the secondary windings are represented by stages of a wavelet filter bank where the dimensions of such a filter bank depend on the number of turns of primary windings and secondary windings. The basic building block consists of stages of the wavelet filter bank. Transformer total response is composed of the sum of responses of all stages, which depends on the nature of the primary current. Using the wavelet filter model, the losses due to eddy currents, leakage flux, and inrush currents have been studied. The proposed wavelet filter model has been found to be suitable for power transformer inrush currents including high frequency transient effects.
4 citations