Showing papers on "Bessel filter published in 2011"

Spectral Multipliers for Multidimensional Bessel Operators

Abstract: In this paper we prove L p -boundedness properties of spectral multipliers associated with multidimensional Bessel operators In order to do this we estimate the L p -norm of the imaginary powers of Bessel operators We also prove that the Hankel multipliers of Laplace transform type on (0,∞) n are principal value integral operators of weak type (1,1)

A Bessel polynomial approach for solving general linear Fredholm integro-differential-difference equations

Abstract: In this paper, to find an approximate solution of general linear Fredholm integro-differential-difference equations (FIDDEs) under the initial-boundary conditions in terms of the Bessel polynomials, a practical matrix method is presented. The idea behind the method is that it converts FIDDEs to a matrix equation which corresponds to a system of linear algebraic equations and is based on the matrix forms of the Bessel polynomials and their derivatives by means of collocation points. The solutions are obtained as the truncated Bessel series in terms of the Bessel polynomials Jn (x) of the first kind defined in the interval [0, ∞). The error analysis and the numerical examples are included to demonstrate the validity and applicability of the technique.

Asymptotic expansions for the Bessel transformations with high oscillations by using the homotopy technique

Abstract: In this paper, we establish the asymptotic expansions for the integration containing the Bessel functions with high oscillations by using the homotopy technique The proposed method is constructed by approximating the non-oscillatory or low-oscillatory factor in practice Two cases are considered, that is, the case 0 [image omitted] [a, b] and the case 0∈[a, b], where [a, b] denotes the integration interval The efficiency of the technique and the correctness of the theory are shown by several examples

Analysis and Implement of ECG Front-End Signal Processing Circuit

Abstract: In order to reduce the noise disturbance to ECG signals, ECG front-end signal processing method is proposed in this paper. In this method, the RFI filter is a bridge type differential low-pass filter. The input amplifier is high precision instrument amplifier AD8220 which has JFET input stage characteristic, the low-pass filter is a five order Bessel filter which has the most flat amplitude and phase response, and the right leg driving circuit is precision operational amplifier OP2177 which has low input bias current. The method is characterized with simpleness, easy integration, good stability and high precision. It is significant for the future electrocardiogram instrument.

Unitary Systems and Bessel Generator Multipliers

Abstract: A Bessel generator multiplier for a unitary system is a bounded linear operator that sends Bessel generator vectors to Bessel generator vectors. We characterize some special (but useful) Bessel generator multipliers for the unitary systems that are ordered products of two unitary groups. These include the wavelet and the Gabor unitary systems. We also provide a detailed exposition of some of the history leading up to this work.

Bessel filters using simulated inductor

Abstract: The use of passive component namely the inductor in analog circuits is very difficult at low frequencies, because the size of the inductors becomes very large and the fabrication of inductors in IC is also not possible to suite with the modern advancement of IC technology In this paper, the method of simulating the passive component L using Generalized Impedance Converter (GIC) is presented This simulated inductor is applied for the realization of Bessel filters The circuit simulation is done using PSPICE The design and frequency response of low pass, high pass and all pass filters are also presented

Globally convergent algorithm to find the zeros of the cross-product of Bessel functions

Abstract: This paper shows the construction of an algorithm to calculate the roots of both, the cross-product of Bessel functions respectively of their first derivatives. The algorithm has shown globally convergent behavior for a large range of values of the argument and of the order of the Bessel functions with the desired accuracy to machine precision.

Bessel Nulls Recovery in Spherical Microphone Arrays for Time-Limited Signals

Abstract: Spherical microphone arrays have recently been developed for a wide range of applications. In particular, scanning arrays in open-sphere configuration have been employed for room acoustics analysis, based on room impulse response measurements. However, it has been shown that the simple single-sphere configuration suffers from ill-conditioning around the zeros of the spherical Bessel function, and so alternative configurations, typically more complex, such as dual-sphere and single-sphere with cardioid microphones, have been proposed to overcome the effect of the Bessel nulls. This paper shows that in the particular case of time-limited signals, for example in room impulse response measurements, the ill-conditioning due to the spherical Bessel functions can be reduced using nonuniform sampling in the frequency domain. Following a presentation of the theory and a simulation study, an experimental example is presented for use of the method in a single-sphere measurement in an auditorium.

Spherical Bessel Filter for 3D object detection

Abstract: The detection of 3D objects and landmarks in arbitrary orientations is one of the most challenging tasks in biomedical 3D image analysis. In this paper we introduce the spherical Bessel Filter (BF) for rotation invariant 3D object detection tasks. The BF is based on the Harmonic Filter (HF) and thus inherits all the gentle properties of the HF, in particular the data driven adaptability and the processing speed. In contrast to the HF the BF benefits from a better object representation based on local spherical Fourier basis functions leading to noticeably better object detections and localizations.

Scale space smoothing, image feature extraction and bessel filters

Abstract: The Green function of Mumford-Shah functional in the absence of discontinuities is known to be a modified Bessel function of the second kind and zero degree. Such a Bessel function is regularized here and used as a filter for feature extraction. It is demonstrated in this paper that a Bessel filter does not follow the scale space smoothing property of bounded linear filters such as Gaussian filters. The features extracted by the Bessel filter are therefore scale invariant. Edges, blobs, and junctions are features considered here to show that the extracted features remain unchanged by varying the scale of a Bessel filter. The scale invariance property of Bessel filters for edges is analytically proved here. We conjecture that Bessel filters also enjoy this scale invariance property for other kinds of features. The experimental results presented here confirm our conjecture of the scale invariance property of the Bessel filters.

Evaluation of Bit Error Rate (BER) in WLAN IEEE 802.11a with radio over fiber (RoF) downlink system

Abstract: In this paper, the system suggested for improvement of Bit Error Rate (BER) in WLAN IEEE 802.11a with Radio over Fiber (RoF) technology in downlink system to increase reliability of the system and to make it flexible and satisfy the future requirements. The downlink blocks operating at 1550 nm using 50 Km bidirectional Single Mode Fiber (SMF) with 64 QAM modulations using RF modulated frequency 5.8 GHz (UNII) and 54 Mbps data rate. The improvement of BER of 802.11a is done by using QAM modulation and components of RoF likes using SMF and Bessel filter. The evaluation of performance of BER is done by using OPTISYSTEM for simulation results.

Movement detection based on filter with symmetric impulse response

Abstract: The continuous-time detection of movement is a time-domain operation. It usually requires lowpass filters ensuring small waveform distortion. To achieve small time-domain distortion, the filters approximating linear phase, such as Bessel and Gaussian filter, are often used. However, these filters have poor selectivity. Both, high selectivity and nearly linear phase are obtained by using the filters with symmetric impulse response. In this paper, we propose a simple method for the detection of movement, which uses this type of filter. We illustrate the features of the method in the measurement of the movements during biceps curl exercise. The method proved to be robust with high accuracy of the detection. Furthermore, it is suitable for application in physical rehabilitation where variety of changes in motoric functions can be detected.

Approximation of Analytic Functions by Bessel's Functions of Fractional Order

Abstract: We will solve the inhomogeneous Bessel's differential equation , where is a positive nonintegral number and apply this result for approximating analytic functions of a special type by the Bessel functions of fractional order.

Design of narrow-band FIR filter with low group delay and piecewise polynomial impulse response

Abstract: This paper presents a design method for piecewise polynomial digital filter with very low group delay. The first step to design such filter is to determine filter coefficient of the approximately linear phase, low delay and quasi-equiripple FIR lowpass by using existing design procedure. After that, the polynomial coefficients are obtained using transform which is derived here. The main advantage of the FIR filter with piecewise polynomial impulse response is in the fact that it can be efficiently implemented by using recursive or Farrow structure, depending on the application. In this way, the number of multiplications can be significantly reduced compared to the conventional FIR filter.

Shock Data Filtering Consequences

Abstract: The plateau of the Pseudo Velocity Shock Spectrum (PVSS) plotted on Four Coordinate Paper (4CP) shows the severe frequency range of the shock. Peak modal stress is proportional to PV [1, 2, 3, 4]; hence filtering effects can be quantified according to changes in the plateau. Maximum acceleration usually defines the high frequency extent of the plateau and low pass filtering reduces the peak acceleration levels of shock data. Thus low pass filtering hides the high frequency content of the shock in the shock analysis. This is demonstrated in both the time history as well as the PVSS. Both Butterworth and Bessel filters are compared to try and see if the linear phase attribute of the Bessel filter causes any changes in the PVSS.

Analytic partial wave expansion and integral representation of Bessel beam

Abstract: This paper describes the partial wave expansion and integral representation of Bessel beams in free space and in the presence of dispersion. The expansion of the Bessel beam wavepacket with constant spectrum is obtained as well. Furthermore, the sum of a triple Legendre polynomial product of same order but different argument follows naturally from the partial wave expansion. The integration of all Bessel beams over all conical angles is shown to have a simple series representation, which confirms the equivalence between the results for both expansion and integral representation.