Topic
Bessel filter
About: Bessel filter is a research topic. Over the lifetime, 656 publications have been published within this topic receiving 16808 citations.
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TL;DR: The modified Bessel collocation method is presented to obtain the approximate solutions of the linear Lane-Emden differential equations using the improvement of the Bessel polynomial solutions with the aid of the residual error function.
41 citations
TL;DR: The theory for multiple Bessel beams is discussed which has been shown to be the source of the wide width of the efficiency curve of the third-harmonic generation observed in experiments.
Abstract: Taking Bessel beams ({ital J}{sub 0} beam) as a representation of a conical beam, and a slowly varying envelope approximation (SVEA) we obtain the results for the theory of third-harmonic generation from an atomic medium. We demonstrate how the phenomenon of self-phase-matching is contained in the transverse-phase-matching integral of the theory. A method to calculate the transverse-phase-matching integral containing four Bessel functions is described which avoids the computer calculations of the Bessel functions. In order to consolidate the SVEA result an alternate method is used to obtain the exact result for the third-harmonic generation. The conditions are identified in which the exact result goes over to the result of the SVEA. The theory for multiple Bessel beams is also discussed which has been shown to be the source of the wide width of the efficiency curve of the third-harmonic generation observed in experiments. {copyright} {ital 1996 The American Physical Society.}
41 citations
TL;DR: The Taylor series expansion is used to transform the design problem of a fractional delay filter into the one of a first-order differentiator such that the conventional finite-impulse response and infinite-Impulse response differentiators can be applied to design a fractionAL delay filter directly.
Abstract: In this paper, the Taylor series expansion is used to transform the design problem of a fractional delay filter into the one of a first-order differentiator such that the conventional finite-impulse response and infinite-impulse response differentiators can be applied to design a fractional delay filter directly. The proposed structure is more efficient than the well-known Farrow structure in terms of filter coefficient storage because only one first-order differentiator needs to be designed and implemented. Moreover, one design example is demonstrated to illustrate the effectiveness of this new design approach.
40 citations
Patent•
29 Jul 1999
TL;DR: In this paper, an artifact rejector is constructed to generate and store repetitive averaged physiologic-event-signal data based upon a substantially stable time relationship between corresponding physiologic event-Signal data and heart-beat-related signal.
Abstract: An artifact rejector for repetitive physiologic-event-signal data generated from electronically-controlled physiologic-event-measuring equipment includes a physiologic-event-signal averager in communication with such physiologic-event-measuring equipment. The artifact rejector is constructed to generate and store repetitive averaged physiologic-event-signal data based upon a substantially stable time relationship between corresponding physiologic-event-signal data and heart-beat-related-signal data. The repetitive averaged physiologic-event-signal data includes less noise than the repetitive physiologic-event-signal data. The artifact rejector generates and continuously updates an averaged-data template by storing such repetitive averaged physiologic-event-signal data for a preselected number of measured physiologic events. The artifact rejector also includes a physiologic-event-noise estimator and a physiologic-event-noise monitor in communication with such physiologic-event-measuring equipment, and capable of instructing the monitor to adjust the measurement cycle based upon estimated, monitored noise. The averager preferably includes a sharp roll-off, low pass filter and examples include a fourth-order Bessel filter, two cascaded, identical second-order Bessel filters, an elliptic filter, a Tchetschebyscheff filter, or finite impulse response filters. The heart-beat-related signal is preferably an ECG signal. A method of artifact rejection includes generating and storing repetitive averaged physiologic-event-signal data based upon a substantially stable time relationship between corresponding physiologic-event-signal data and heart-beat-related-signal data, with the repetitive averaged physiologic-event-signal data including less noise than the repetitive physiologic-event-signal data.
39 citations
TL;DR: In this article, the radius of convexity of two normalized Bessel functions of the first kind was determined in the case when the order is between $-2$ and $-1.$.
Abstract: The radius of convexity of two normalized Bessel functions of the first kind are determined in the case when the order is between $-2$ and $-1.$ Our methods include the minimum principle for harmonic functions, the Hadamard factorization of some Dini functions, properties of the zeros of Dini functions via Lommel polynomials and some inequalities for complex and real numbers.
39 citations