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Showing papers on "Bessel filter published in 1999"


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


Proceedings ArticleDOI
30 May 1999
TL;DR: A novel circuit implementation of a CMOS log-domain integrator that does not require placing of MOSFETs in separated wells, and therefore allows very compact filters, which are fully compatible with modern standard CMOS technologies.
Abstract: A novel circuit implementation of a CMOS log-domain integrator is presented. Unlike most other implementations, it does not require placing of MOSFETs in separated wells, and therefore allows very compact filters, which are fully compatible with modern standard CMOS technologies. Besides the saving of chip area, this also helps to reduce parasitic capacitances. The most important advantage of this circuit is the very low minimum required supply voltage of only two saturation voltages plus one gate-to-source voltage of a weakly inverted MOSFET. This is fully compatible with the minimum required supply voltage of digital gates implemented in the same technology. The integrator was used as a building block for a 5th-order Bessel filter, which was simulated with the transistor parameters of a 0.5 /spl mu/m CMOS technology.

24 citations


Proceedings ArticleDOI
16 May 1999
TL;DR: In this paper, a 5/sup th/low-pass continuous-time Bessel filter was designed using a CMOS transistors-only approach and a pseudo-differential topology, achieving a 57 dB minimum dynamic range even under 0.9 V supply voltage.
Abstract: This paper presents the design of a 5/sup th/ low-pass continuous-time Bessel filter, which is realized using a CMOS transistors-only approach and a pseudo-differential topology. It achieves a 57 dB minimum dynamic range even under 0.9 V supply voltage. The power consumption is as low as 10.5 /spl mu/W at the nominal 100 kHz cutoff frequency, while the total chip area is only 0.2 mm/sup 2/.

22 citations


Journal ArticleDOI
23 Apr 1999

15 citations


Journal ArticleDOI
TL;DR: A technique for producing a Bessel function correlation output for an arbitrary input pattern by spatially modulating the phase encoded on the filter by modulation of the diffraction efficiency of the phase grating.
Abstract: We report on a technique for producing a Bessel function correlation output for an arbitrary input pattern. The central dark spot at the center of the Bessel function correlator output is narrower than the width of the normal correlation spot and can be extremely useful for locating the center of the correlation signal. The Bessel function is produced by convolution of the extremely sharp correlation produced by an inverse filter with the Bessel function and is encoded with a single phase-only liquid-crystal spatial light modulator. To encode amplitude information on the filter, we spatially modulate the phase encoded on the filter. Amplitude modulation is obtained by modulation of the diffraction efficiency of the phase grating. Experimental results are presented.

14 citations


Proceedings ArticleDOI
01 Oct 1999
TL;DR: In this paper, the design and results of a Bessel low pass filter at 7.5 GHz for high speed (optical) communication applications are described, where the equivalent circuit of a lumped element filter is transformed into a planar circuit mounted in a rectangular waveguide channel each reactance of the filter is realized by an electrically short transm on line.
Abstract: This paper describes the design and results of a Bessel low pass filter at 7.5 GHz for high speed (optical) communication applications. The equivalent circuit of a lumped element filter is transformed into a planar circuit mounted in a rectangular waveguide channel Each reactance of the filter is realized by an electrically short transm on line. To this end, a combianation of microstrip line and suspended stripline had to be used to cope with the widely varying impedance levels and to achieve a compact low loss filter.

10 citations


Journal ArticleDOI
James S. Ball1
TL;DR: An efficient algorithm is developed for the automatic calculation of the zeros of Bessel functions of arbitrary order, Coulomb wave functions, and other special functions without any actual functional evaluations.
Abstract: An efficient algorithm is developed for the automatic calculation of the zeros of Bessel functions of arbitrary order, Coulomb wave functions, and other special functions. Remarkably, this can be done without any actual functional evaluations. Limitations and generalizations are discussed.

10 citations



Proceedings ArticleDOI
K. Gopalan1
22 Aug 1999
TL;DR: In this paper, a Fourier-Bessel series (FB) expansion of speech signals is used for voice disguising and spectrum modifying applications, and a reasonable quality of altered speech at low bit rate coding can be achieved.
Abstract: Speech modification for voice disguising and spectrum modifying applications has been explored using a Fourier-Bessel series (FB) expansion of speech signals. With the approximately bandpass spectrum of the first order Bessel functions, the FB expansion coefficients may be altered and the expansion may be truncated to yield a desired speech quality in the modified speech. Results demonstrate that reasonable quality of altered speech at low bit rate coding can be achieved.

5 citations


Journal ArticleDOI
TL;DR: In this article, the axially symmetric, radial vibration frequency equation of multilayered cylinders made of the same materials in plain strain state is studied, and it is proved that the frequency equations of several contact hollow cylinders can be replaced by a single hollow cylinder, so that the solving process is greatly simplified.
Abstract: In this paper the axially symmetric, radial vibration frequency equation of multilayered cylinders made of the same materials in plain strain state is studied. It is proved in this paper that the frequency equation of several contact hollow cylinders can be replaced by the frequency equation of a single hollow cylinder, so that the solving process is greatly simplified. Some recursion formulae of Bessel functions are derived from such practical problems as well.

2 citations


Journal Article
TL;DR: In this article, the utility of the linear combination of Bessel functions composes exact solution of an impulsive propagation of a wave in heterogeneuus discrete medium, which may put a way to the final solution of the propagation of the shock waves.
Abstract: The new research on the propagation of the elastic waves in discrete medium has a result, which is the utility of the linear combination of Bessel function composes exact solution of an impulsive propagation of a wave in heterogeneuus discrete medium. Make use of the perfect characters of Bessel functions, this result may put a way to the final solution of the propagation of the shock waves.


Proceedings ArticleDOI
20 Jul 1999
TL;DR: In this article, the authors present an analysis of the Bessel function of the signal envelope of a sine wave that is the nth multiple of the modulation frequency, which can be used on their own to determine range based on tabulated values of Bessel functions.
Abstract: Frequency-modulated continuous wave radar systems have been used for many years to determine range and velocity in a wide variety of military and commercial applications. The modulation waveform can be sinusoidal, triangular or sawtooth. Each form has its advantages, but, since the triangular and sawtooth modulation can be approximated with a sinusoidal modulation, the analysis in this paper will concentrate on sinusoidal modulation. For moving targets, the envelope of the signal used for determining the Doppler frequency is a function that varies according to the range. If the mixing is performed with a sine wave that is the nth multiple of the modulation frequency, then the envelope is an nth-order Bessel function that varies according to the range. These envelopes can be used on their own to determine range based on tabulated values of the Bessel function. A second approach is to use the difference between two Bessel functions of different orders to identify a certain range. The choice of Bessel functions depends on the carrier frequency and the target range. Amplifiers can be used to modify the identification range.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Patent
14 Jun 1999
TL;DR: In this paper, a phase shifter network consisting of N number of all-pass filters and a low-pass bessel filter is proposed to demodulate a frequency-modulated signal.
Abstract: An approach for demodulating a frequency-modulated signal involves processing a frequency-modulated signal with a phase shifter network to provide a demodulated signal that has a relatively constant amplitude around the center frequency of the frequency-modulated signal and that exhibits a relatively linear phase change over an operational frequency range. Embodiments of the invention include a phase shifter network comprising N number of all-pass filters and a phase shifter network comprising a low-pass bessel filter.