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.

Method and apparatus for reducing correlated errors in subband coding systems with quantizers

Abstract: A method and apparatus for reducing correlated errors in subband coding systems with quantizers is disclosed. A subband coding system comprises a plurality of subband analysis filters to divide the frequency spectrum of the input signal into subbands, individual subband quantizers for coding each subband by a preselected number of quantization levels, corresponding subband decoders and subband synthesis filters. The transfer function of each of the subband synthesis filters is advantageously determined based on the transfer functions of the subband analysis filters as well as on the characteristics of the quantizer used to code the corresponding subband. Specifically, the synthesis filter transfer functions may be based on a perfect reconstruction filter bank or a quadrature mirror filter bank, as well as on the gain factors of a gain plus additive noise linear model for the Lloyd-Max quantizers used to code the corresponding subbands. That portion of the error between the input signal and the replica signal as reconstructed by the system which is correlated to the input signal may be advantageously reduced or eliminated, irrespective of that portion of the error which is uncorrelated to the input signal. Thus, the total error in a final signal may be advantageously reduced by the subsequent application of prior art techniques for the reduction of random, uncorrelated noise.

Efficient implementation of nearly perfect reconstruction FIR cosine-modulated filterbanks

Abstract: In this paper, a new fast implementation of nearly perfect reconstruction finite impulse response (FIR) cosine-modulated filterbanks is shown. A new expression for the analysis bank has been developed, and based on it, an efficient implementation structure is obtained for specific prototype filter lengths. The new computationally efficient algorithm can be applied to both the conventional cosine-modulated filterbank and the Koilpillai-Vaidyanathan pseudo-quadrature mirror filterbank. We also show how the implementation cost (measured in multiplications and additions per input sample) is reduced.

Time-Frequency and Time-Scale Signal Analysis by Harmonic Wavelets

Abstract: New details of the theory of harmonic wavelets are described and provide the basis for computational algorithms designed to compute high-definition time-frequency maps. Examples of the computation of phase using the complex harmonic wavelet and methods of signal segmentation based on amplitude and phase are described.

Partial spectrum reconstruction using digital filter banks

Abstract: The problem of reconstructing a part of the spectrum is reduced to designing the filter bank to satisfy a set of conditions. For the case considered here, these conditions cannot be satisfied simultaneously, so perfect reconstruction is not possible. The necessary and sufficient conditions on the filters so that the resulting filter bank cancels most alias components are found. Such filter banks are called partial alias cancellation filter banks. The product of the polyphase transfer matrices of these filter banks must be a block pseudocirculant matrix. An algorithm design procedure is discussed, and examples are given to demonstrate the theory. >

High input impedance voltage-mode universal filter and quadrature oscillator

Abstract: A new single input and five outputs high input impedance voltage-mode universal biquadratic filter using three DVCCs, five passive components is presented The proposed circuit offers the following