Showing papers on "Quadrature mirror filter published in 1984"

Quadrature mirror filter design in the time domain

Abstract: A new technique for designing quadrature mirror filters is described. The formulation, carried out in the time domain, is shown to result in an optimization problem requiring minimization of a quartic multinomial. An iterative solution is suggested which involves (computation of) the eigenvector of a matrix with a dimensionality equal to one half the number of filter taps. Our experiments show that convergence to the optimum tap weights is stable, and the accuracy of the final solution is limited only by the accuracy of the eigenvalue-eigenvector routine. As in an earlier technique, the user can specify the stop: band frequency the relative weights of the passband ripple energy and the stopband residual energy, and, of course, the number of filter taps.

New quadrature mirror filter structures

Abstract: This paper introduces new quadrature mirror filter (QMF) structures for the frequency domain analysis and synthesis of digital signals. The conventional QMF technique is first extended to cover complex quadrature mirror filters (CQMF) in which a digital signal is split into N adjacent complex subbands where the real and imaginary parts are subsampled by 1/2N with respect to the original signal. The computational complexity of QMF banks is then analyzed and a new scheme which reduces the computational complexity by about a factor of two over conventional QMF implementations is proposed. Finally, the filter design tradeoffs are discussed and the microprogramed implementation of QMF banks is evaluated.

Computationally efficient QMF filter banks

Abstract: This paper introduces a computationally efficient technique for splitting a signal into N equally spaced sub-bands subsampled by 1/N and for near perfectly reconstructing the original signal from the sub-band signals. This technique is based on a multirate approach where some operations are nested to decrease the computation load. Simulation results show that the performances are comparable to that of conventional quadrature mirror filters, but with a very significant reduction in computational complexity.

An analytical formula for the design of quadrature mirror filters

Abstract: Quadrature mirror filters have an outstanding relevance in the implementation of filter banks for dividing the speech signal into frequency bands and for reconstructing it from these subbands. An analytical formula is given, which allows one to optimize the design of the basic low-pass FIR filter by means of a straight nonlinear minimization procedure.

Computationally efficient qmf filter banks

Abstract: ted from the subsampled channel signalsThis paper introduces a computationally eff i— In the following, we derive the N band-passcient technique for splitting a signal into Nequally spaced sub-bands suhsampled by 1/N and fornear perfectly reconstructing the original signalfrom the sub-band signals This technique is basedfilters hk(n) by frequency translation (fig 1)from a prototype L-tap linear phase low-pass filterh(n) with cut—off frequency at f /4N, and withaon a multirate approach where some operations arenested to decrease the computation load Simulation hk(n) = h(n)coa[2v(2k+l) (2n—N)/8N] (1) results show that the performances are comparableto that cf conventional quadrature mirror filters,but with a vary significant raduction in computa—tional complexityThe s—transforms of the band—pass filtara are givenas a function of the s—transform H(s) of h(n) by w N(2k+l) 2(2k+l) N(W z) Hk(z) =INTRODUCTIONConventional quadrature mirror filter (QMF) W —N(2k+l) —2(2k+l) + H(W z)