Bessel filter

About: Bessel filter is a research topic. Over the lifetime, 656 publications have been published within this topic receiving 16808 citations.

Design of digital filters with amplitude and group delay specifications

Abstract: This paper considers the design of a digital filter with prescribed magnitude and group delay specifications. First, we outline the derivation of the phase and group delay functions of an Nth order digital Laguerre filter and show that the group delay function of the filter can be written as a ratio of quadratic functions in the filter coefficients. Then, we formulate our filter design problem as a constrained L/sub 2/ space minimization problem in which the performance requirement on the group delay and magnitude in the passband are treated as constraints while minimizing the L/sub 2/ norm of the error function between the designed and the desired filters. Methods for solving the proposed nonlinear optimization problem axe outlined. Numerical results are presented to illustrate the usefulness of the proposed method. As a special case, corresponding results for general FIR filters axe also derived.

An accurate gate delay model for high speed digital and analog circuits

Abstract: At present, most of simulation programs can characterize gate delays of microwave transistors. However, the delay is mostly approximated by means of a first-order differential equation only. In the paper, a more accurate way is suggested which is based on an appropriate second-order Bessel function. The delay model is implemented to a slightly but efficiently modified classic MESFET model. The proposed model does not create spurious oscillations that are typical for any LC approximations, and the simulation times are comparable with those obtained without the delay model. Properties of the implementation of the second-order Bessel function are demonstrated by an analysis of a tunable distributed microwave oscillator.

Determination of the optimum electrical bandwidth for spectral slicing

Abstract: The implementation of wavelength division multiplexing (WDM) in communication access networks is dependent upon the availability of low cost optical sources. One possible alternative to lasers is to employ slices of a broadband optical source obtained via optical filters, which may be tuneable. This paper considers the behaviour of such a spectrally sliced optical transmission system as a function of the bandwidth of a realistic receiver electrical filter for the first time. The treatment includes distortion from optical fibre dispersion over several kilometres of fibre. The optimum ratio between the electrical bandwidth and the optical bit rate is found to be ~0.6 for a fifth-order Bessel filter

Electrical noises reduction in nanopores experiments based on consensus filter

Abstract: Nanopore has developed into an indispensable tool for single molecules experiments, where useful information about the characteristics of DNA/RNA can be obtained from the flowing of ionic current elicited by individual molecules as they traverse a single nanometer-scale aperture. However, due to the relatively high background current noise and low measurement bandwidth, it is difficult to distinguish the molecule-specific signals from the intrinsic noises of the nanopore recording systems, which impeded its application in DNA sequencing. In this paper, we present a novel consensus filter-based noise reduction approach, which considerably improves the accuracy of the noise-filtered current traces and the signal-to-noise ratios (SNRs). The new approach is compared to the conventional Bessel filters and validated by analyzing simulated representative translocation data as well as alpha-Hemolysin (α-HL) nanopore experimental data. It is demonstrated that the high frequency noise generated by the voltage noise of the amplifier and Analog-to-Digital converter circuits (ADC) can be significantly reduced and some hidden short-lived translocation events can be recovered with satisfying accuracy beyond the conventional limitations of the Bessel filters.