The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform

Anil Kumar - One of the best experts on this subject based on the ideXlab platform.

  • design of m channel cosine modulated filter bank using modified exponential window
    Journal of The Franklin Institute-engineering and Applied Mathematics, 2012
    Co-Authors: Anil Kumar, B Kuldeep
    Abstract:

    Abstract In this paper, an improved Exponential window is developed for designing M-channel cosine-modulated pseudo QMF banks. The Exponential window is modified by adding third parameter (ρ), which improves the spectral characteristic of a window in terms of smaller ripple ratio, wider main lobe width with improved side lobe roll-off ratio. When it is exploited for designing multi-channel cosine modulated filter banks, the modified Exponential window gives better performance for higher band as compared to lower band. In addition to this, the modified Exponential window performs better performance at lower stopband attenuation. When compared with modified Cosh and Kaiser windows, the modified Exponential windows performs better in terms of Amplitude Distortion, aliasing Distortion (AD) and computational time (CPU time) for the same design specifications. Several examples are included to illustrate the effectiveness of this window in the field multirate systems designing.

  • an improved closed form design method for the cosine modulated filter banks using windowing technique
    Applied Soft Computing, 2011
    Co-Authors: Anil Kumar, G K Singh, R S Anand
    Abstract:

    This paper presents an improved closed form method for designing cosine modulated filter banks with prescribed stopband attenuation and channel overlap. The proposed method is based on optimum passband frequency, which is calculated using empirical formulas instead of using time consuming single or multivariable optimization. Different window functions are employed to design the prototype filter with the novelty of exploiting spline functions in the transition region of the ideal filter. Several design examples are included to show the increased efficiency of the proposed method over other exiting methods in terms of computation time, Amplitude Distortion (e"a"m) and aliasing Distortion (e"a). An application of the proposed method is considered in the area of subband coding of the ECG and speech signals.

  • A closed form design method for the two-channel quadrature mirror filter banks
    Signal Image and Video Processing, 2011
    Co-Authors: Anil Kumar, G K Singh, R S Anand
    Abstract:

    This paper presents a simple and efficient closed form method for designing two-channel linear phase quadrature mirror filter (QMF) banks with prescribed stopband attenuation and channel overlap. The proposed method is based on optimum passband edge frequency, which is calculated using empirical formulas instead of using optimization algorithm. Different window functions are used to design the prototype filter for QMF banks. When compared to other existing methods, the proposed method reduces computation time (CPU time) and Amplitude Distortion (e_ am ), which results in a simpler and efficient design procedure for the applications where the design must be carried out in real or quasi-real-time. Several design examples are included to illustrate the proposed method and its improved performances over other exiting methods. An application of the proposed method is considered in the area of subband coding of ultrasound image.

R S Anand - One of the best experts on this subject based on the ideXlab platform.

  • an improved closed form design method for the cosine modulated filter banks using windowing technique
    Applied Soft Computing, 2011
    Co-Authors: Anil Kumar, G K Singh, R S Anand
    Abstract:

    This paper presents an improved closed form method for designing cosine modulated filter banks with prescribed stopband attenuation and channel overlap. The proposed method is based on optimum passband frequency, which is calculated using empirical formulas instead of using time consuming single or multivariable optimization. Different window functions are employed to design the prototype filter with the novelty of exploiting spline functions in the transition region of the ideal filter. Several design examples are included to show the increased efficiency of the proposed method over other exiting methods in terms of computation time, Amplitude Distortion (e"a"m) and aliasing Distortion (e"a). An application of the proposed method is considered in the area of subband coding of the ECG and speech signals.

  • A closed form design method for the two-channel quadrature mirror filter banks
    Signal Image and Video Processing, 2011
    Co-Authors: Anil Kumar, G K Singh, R S Anand
    Abstract:

    This paper presents a simple and efficient closed form method for designing two-channel linear phase quadrature mirror filter (QMF) banks with prescribed stopband attenuation and channel overlap. The proposed method is based on optimum passband edge frequency, which is calculated using empirical formulas instead of using optimization algorithm. Different window functions are used to design the prototype filter for QMF banks. When compared to other existing methods, the proposed method reduces computation time (CPU time) and Amplitude Distortion (e_ am ), which results in a simpler and efficient design procedure for the applications where the design must be carried out in real or quasi-real-time. Several design examples are included to illustrate the proposed method and its improved performances over other exiting methods. An application of the proposed method is considered in the area of subband coding of ultrasound image.

Edwin L Carstensen - One of the best experts on this subject based on the ideXlab platform.

  • finite Amplitude Distortion and its relationship to linear derating formulae for diagnostic ultrasound systems
    Ultrasound in Medicine and Biology, 1996
    Co-Authors: T Christopher, Edwin L Carstensen
    Abstract:

    Formulation of indices that can be used as predictors of biological effects of ultrasound involves a process called derating, in which measurements of the sound field made in water are extrapolated to estimates of the magnitude of the sound fields in the tissues of the body. All indices that have been formulated up to the present time assume that the propagation of ultrasound is linear. In fact, under most exposure conditions for which biological effects may be a concern, sound propagation is highly nonlinear. A nonlinear propagation model has been used in this study to evaluate the nature of the effects that occur under realistic exposure conditions encountered in diagnostic procedures. Because of the way that the thermal index is defined, it turns out that ignoring nonlinear propagation leads to underestimates of tissue temperature increments that typically are less than 40%. As currently implemented, the mechanical index may be underestimated by more than a factor of two because it ignores the saturation of the sound fields that result from nonlinear propagation. For large propagation distances in soft tissues (e.g., 10 cm at 3 MHz in liver); however, it is physically difficult to exceed tissue pressures corresponding to MI > 2 because of these same saturation phenomena.

L. Benmesbah - One of the best experts on this subject based on the ideXlab platform.

  • two channel linear phase fir qmf bank minimax design via global nonconvex optimization programming
    IEEE Transactions on Signal Processing, 2010
    Co-Authors: Wk B Ling, L. Benmesbah, Cw T Kok, Wanchi Siu, Kl Teo
    Abstract:

    In this correspondence, a two-channel linear phase finite-impulse-response (FIR) quadrature mirror filter (QMF) bank minimax design problem is formulated as a nonconvex optimization problem so that a weighted sum of the maximum Amplitude Distortion of the filter bank, the maximum passband ripple magnitude and the maximum stopband ripple magnitude of the prototype filter is minimized subject to specifications on these performances. A modified filled function method is proposed for finding the global minimum of the nonconvex optimization problem. Computer numerical simulations show that our proposed design method is efficient and effective.

  • Optimal cosine modulated nonuniform linear phase FIR filter bank design via stretching and shifting frequency response of prototype filter
    2010 7th International Symposium on Communication Systems Networks & Digital Signal Processing (CSNDSP 2010), 2010
    Co-Authors: Charlotte Yuk-fan Ho, B.w.-k. Ling, L. Benmesbah
    Abstract:

    This paper proposes an optimal cosine modulated nonuniform linear phase finite impulse response (FIR) filter bank design. The frequency responses of all the analysis filters and the synthesis filters of the filter bank are derived based on both stretching and shifting the frequency response of the prototype filter. The total aliasing error of the filter bank is minimized subject to a specification on the maximum Amplitude Distortion of the filter bank as well as specifications on both the maximum passband ripple magnitude and the maximum stopband ripple magnitude of the prototype filter. This filter bank design problem is actually a functional inequality constrained optimization problem. Our recently developed integration approach is employed for solving the problem. Computer numerical simulation results show that our proposed design method outperforms existing design methods.

Kl Teo - One of the best experts on this subject based on the ideXlab platform.

  • two channel linear phase fir qmf bank minimax design via global nonconvex optimization programming
    IEEE Transactions on Signal Processing, 2010
    Co-Authors: Wk B Ling, L. Benmesbah, Cw T Kok, Wanchi Siu, Kl Teo
    Abstract:

    In this correspondence, a two-channel linear phase finite-impulse-response (FIR) quadrature mirror filter (QMF) bank minimax design problem is formulated as a nonconvex optimization problem so that a weighted sum of the maximum Amplitude Distortion of the filter bank, the maximum passband ripple magnitude and the maximum stopband ripple magnitude of the prototype filter is minimized subject to specifications on these performances. A modified filled function method is proposed for finding the global minimum of the nonconvex optimization problem. Computer numerical simulations show that our proposed design method is efficient and effective.