最新刊期
卷 ， 期 12 ， 1996
- 摘要：Based on new advance in the multiple forward scattering theory of radio propagation in a random meidum, formula are derived for the study of mean arrival time of pulse signal propagating through the ionospheric irregularities, which takes into account of the refractive and dispersive effects of the background ionosphere on the mean arrival time ,and of the multiple scattering and dispersive effects of the ionospheric electron density irregularities embeded in the background ionosphere. Under high-freqency approximation and asumption of a horizontally stratified background ionosphere, formula are given for calculating the refractive effect of the background ionosphere,the first order dispersive effect of the background ionosphere,the multiple forward scattering effect of the ionospheric electron density irregularities and its first order dispersive effect on the mean arrival time.With a specified background ionosphere,above ionospheric effects on the mean arrival time are studied with emphesis to variations of the scattering effect with the spectrum index ,inner size and outer size of irrgularities. Results demonstrate that the scattering effect of irregularities is relatively important with respect to the refractive effect of the background ionosphere in certain cases, and that it is must taken into account in practical applications.关键词：Mean arrival time of pulse signal;Ionospheric irregularities;Multiple forword scattering;Precise ranging.2|155|15更新时间：2025-12-08
- 摘要：We address the problem of for phased array pulses Doppler radars estimating directions of arrival （DOA） and Doppler frequences of fluctuating targets signals. Based on new rotational invariance techniques,a blind estimates of DOA and Doppler frequence with unknown array manifold due to array elements uncertainties is proposed in the paper. The new method can resolve the angles of multiple narrowband signals even with the same Doppler frequence each other. The efficiency of the proposed method with uncertainties array is confirmed by computer simulations.关键词：DOA-Doppler frequency estimates;High-resolution array processing;Blind estimates;High-order statistics2|231|32更新时间：2025-12-08
- 摘要：The cross polarization radiation field formulas for a parabolic torus reflector are derived using physical optics in this paper. The cross polarization properties of the torus antenna are deeply investigated with these formulas. Some significant conclusions and numerical results are obtained, which lay a theoretical foundation for this type of antenna realizing the low cross polarization property.关键词：Single offset antenna;Parabolic torus antenna;Cross polarization2|199|3更新时间：2025-12-08
- 摘要：The reflection characteristics of conical horn antenna are investigated by a new method which combines rigorous mode-matching approach with the multimode network theory.The radiation problem is transformed into a transmission problem of the corresponding waveguide structure to avoid the difficulty of the field source problem which is met in the traditional analysis. As a result, the calculation procedure is greatly simplified. Accordant results with those calculated by rigorous diffraction theory are obtained in the analysis for the reflection characteristics of opened circular waveguide. The validity and accuracy of the present method is also verified by comparison of the calculated and the experiment results of VSWR for the conical horn antennas.关键词：Conicl horn antenna;Mode-matching;Multimode network theory2|180|6更新时间：2025-12-08
- 摘要：The V-slot antennas with arbitrary included angles are analyzed by moment method and by using dyadic Green’s function of wedges of second kind. The slots are cut in the Vcurved plates and are fed in the center by two wires. The field distributions on slots and the far field patterns in H-plane both of theory and experiment are given. In the last of this paper, some experimental results of non-V-curved slots are given.关键词：V-slots;antennas;Dyadic Green’s function of wedges;moment method2|145|2更新时间：2025-12-08
- 摘要：It is important for the electronic tracking beam within a phased array radar installed aboard to point to maneuvering targets stably and accurately.A new method is presented in order to realize computer control of electronic tracking beam stabilization. In this method, the real-time compensation algorithm is combined with the adaptive Kalman filtering and implemented in the computer. Computer simulation shows that the method and algorithm is suitable for electronic tracking beam aimming at maneuvering targets accurately on the condition of ship’s motion （pitch and roll）,and real-time implementation in a digital computer is feasible.关键词：Shipborne radar;Phased array radar;maneuvering target;target tracking;computer simulation2|214|8更新时间：2025-12-08
- 摘要：A new method is proposed that joint direction/frequency estimation of multiple narrowband source signals may be performed by appropriate processing of data from particular types of arrays. Its main advantage is that it does not require searching through a 2-D signal subspace nor rooting of polynomial functions of two variables. The potential capability is demonstrated by Monte Carlo simulation.关键词：array;algorithm;Direction/frequency estimation2|145|20更新时间：2025-12-08
- 摘要：This paper has discussed an adaptive equalization technique for analog-digital-analog cipter system.关键词：自适应均衡;幅频波动;群时延波动;均衡器;幅频特性;群时;特性3|62|1更新时间：2025-12-08
- 摘要：A new method for detection of moving trajectory of pixel-sized target from a time sequence in high noise environments is presented in this paper. Based on the continuity of the moving trajectory of target, the structure of a quasi-continuity filter（QCF） is built. And a forwardbackward filter algorithm is used to filter most of noise pixels out effectively. Then the properties of trajectory are embedded in an objective function and the trajectory detection problem becomes the problem of minimizing the given objective function. Furthermore, A* algorithm can be used to solve a shortest path problem on a weighted graph to get the target moving trajectory. Finally, experiments will show the advantage of this method for detection of arbitrary target trajectories in high noise environments without the major drawback of limirted detectability wirthin the predefined trajectory set or massive computation that most other algorithms suffer from.关键词：点目标检测;准连续性滤波;目标函数2|130|17更新时间：2025-12-08
- 摘要：In this paper, wavelet-method of moment （Wavelet-MoM） is applied in solving elecric field integral equations（EFIE）.Accuracy, sparsity and condition number of the expansion matrix are analyzed, comparison with the general used subdomain moment is made. The results show that Wavelet-MoM leads to a sparse expansion matrix, with a higher condition number as its cost. We analyze the sparsity principle and give an explanation to the mechanism of higher condition number. At last, a numerical example is presented to verify our conclusions.关键词：wavelet transform;Wavelet-MoM;Operator expansion;Electric field integral equation2|296|19更新时间：2025-12-08
- 摘要：The finite data estimates of the higher-order moments of a complex signal consisting of random harmonics are analysed. Conditions for the higher-order stationarity and ergodicity are obtained. Explicit formulas for the estimation error and its variance, as well as their limiting large sample values are derived. Finally,the results in reference[2] are shown to be a special case of this paper.关键词：Harmonic random process;Higher-order stationarity;Higher-order ergodicity2|84|1更新时间：2025-12-08
- 摘要：Using the Go and Po methods,the electromagnetic fields in a microwave anechoic chamber setting up a compact two-cylindrical antennas range are analysed in this paper. By calculating and designing,the performance indexs of all microwave absorbate and the electromagnetic fields on all walls of a microwave darkroom are obtained.关键词：Compact two-cylindrical antennas range;Microwave absorate;Microwave Anechoic Chamber2|645|19更新时间：2025-12-08
- 摘要：A new tool for signal analysis-fractional Fourier transform（FRFT）,is introduced in this paper. After the brief introduction of several ways of inducing and some basic properties of FRFT, it is studied in the time-frequency plane and interpreted in view of the classic Fourier transform. The relationship between FRFT and Radon-Wigner transform is also derived. Finally, based on the properties of FRFT,two new possible applications in time-frequency signal analysis are proposed.关键词：Fourier transform;fractional Fourier transform;Time-frequency signal analysis2|1250|120更新时间：2025-12-08
- 摘要：Rapid location method for moving target is discussed, which is based on measuring TOA and DOA of the target using single station and processing using weighted least square estimation and weighted modified extended Kalman Filter. Computer simulation proves it to be right. The algorithm in this paper is of great importance to the practicability of passive location and tracking system.关键词：single station;Passive location;Kalman filter7|300|57更新时间：2025-12-08
- 摘要：In this paper,firstly,for a small array the efficient method for estimation of coherent signals direction-the Maximum Likelihood Method is studied. Then,the angle resolution and estimation accuracy of the Maximum Likelihood Method is specially analysed ,and compared with modified spatial smoothing algorithm. Some analogue results are given.关键词：Coherent signal;Direction estimation;Maximum likelihood method2|320|18更新时间：2025-12-08
- 摘要：In this paper, the reconstruction method of the incident field in a waveguide is presented by using of the finite-difference time-domain algorithm, and the absorbing boundary condition for pulse wave propagations in waveguides is studied. If the time-varying curve of the field at any position in the exiting plane of the waveguide is measured out, the accurate reconstruction of the incident field can be implemented by applying the method presented in this paper.关键词：finite-difference time-domain;absorbing boundary condition;microwave pulse;reconstruction2|38|0更新时间：2025-12-08
- 摘要：The problem of routing and capacity assignment in computer communication networks is a complicated nonlinear 0-1 programming. A new optimization method based on Genetic Algorithm for solving this problem is presented.Computing results of real examples of design of CCN demonstrate that with this method the near global optimal solution of the problem can be quickly obtained, and the solution thus obtained has high accuracy.关键词：genetic algorithm;0-1 programming;Computer communication network;routing;Capacity assignment2|176|20更新时间：2025-12-08
- 摘要：Dispersion characteristics of anisotropic guided-wave structures are analyzed by edge-element method in this paper. This approach can be applied to the case in which the permittivity tensor matrix is full, and no spurious solutions appeared in calculation. An eigenvalue equation which can provide direct solution for the propagation constant is also derived. Computed results of anisotropic microstrip line and rectangular dielectric waveguide agree well with data given in the literature, the effectiveness of this method is thus justified.关键词：anisotropic;Edge-element;dispersion characteristics2|46|4更新时间：2025-12-08
- 摘要：For microwave diffraction imaging, we use the WKB approximation to estimate the total field in the dielectric object. Compared to the Born approximation, the amplitude and phase of total field in the object are modified. The Fourier Diffraction Theorem that is quite similar to the one proposed by Wolf（1969） is then derived. By using the extended filtered backpropagation algorithm the object can be reconstructed from the spatial spectrum. The computer simulations show that the quality of image reconstructed by proposed scheme is superior to the one produced by Born approximation.关键词：Microwave imaging;WKB approximation;Spatial spectrum;Extended filtered backpropagation algorithm2|60|1更新时间：2025-12-08
- 摘要：The time domain performance of Ti:Li NbO3 traveling wave modulator is analyzed in this paper. The characteristics in time domain are obtatined by Fourier transformation from the corresponding results in frequency domain. Impulse responst, rectangular impulse response and the effect of electrode attenuation and reflection coefficient on modulation are discussed in detail.关键词：Traveling wave modulator;Time domain response;Impulse response2|44|0更新时间：2025-12-08
- 摘要：The electromagnetic scattering characteristics of partially coated ogive have been calculated by hybrid method and many valuable results have been obtained through analysing the effects of the surface wave on ogive.关键词：surface wave;Travelling wave;Creeping wave;electromagnetic scattering;moment method;Hybrid method.2|49|0更新时间：2025-12-08
- 摘要：In this paper the information crosstalk on EDFAs is examined experimentally when the EDFAs commonly amplify two signal channels. Gain crosstalk and its impacts on system error bit rate are also examined in detail.关键词：Erbium-doped fiber amplifier （EDFA）;fiber communication;Crosstalk;Wavelength division multiplexing （WDM）2|34|0更新时间：2025-12-08
- 摘要：In this paper, we studied the varying rules and affect factors of voltage-sensing and dielectric characteristics when high surge current was applied to SrTiO3 low-voltage varistors prespared by the single-fired method and doped by acceptors Mn2+ and Cu2+. The results show that the Cu+-doped sample has a higher surge-proof capability.关键词：SrTiO3;Varistor;Surge-proof Current2|68|11更新时间：2025-12-08
- 摘要：Gabor expansion, which represents signal in time-frequency space, is a non-or-thogonal expansion. The nonorthogonality of the expansion causes some difficulties in the calculation of the expansion. There exist many papers concentrating on the computation aspect of the expansion. It seem that the non-locality of critical sampling Gabor expansion has not been received enough attention yet. In this paper we will show that when the window function of critical sampling Gabor expansion is continuous or symmetric,the critical sampling Gabor expansion not only can’t always truly reflect the local properties of signals, but exists convergence as well. Examples are also given.关键词：Gabor expansion;Non-locality analysis;Critical sampling2|61|6更新时间：2025-12-08
- 摘要：Stochastic codebook is one of the most important part in Codebook Excited Linear Prediction （CELP） technique. The codebook structure and its searching algorithm mainly affect the synthesized speech quality and the possibility of real-time realization of speech coding systems. The paper proposes a structured stochastic codebook-"Linear-Shifted"Gaussian Codebook, and discusses a set of bi-directional recursive formulations. Single-directional recursive algorithm is then presented, which highly increases the computational speed and reduces complexity by a factor of 1.76. In order to far more decrease the searching complexity, Suboptimal Local Searching strategy is introduced, leading to bi-directional recursive algorithm. With the same quality of synthesized speech, the later algorithm can increase the searching speed twice than that of the former one.关键词：Stochastic codebook;Linear-shifted;Codevector;Single-directional recursive algorithm;Bi-directional recursive algorithm2|39|3更新时间：2025-12-08
- 摘要：Some new voltage mode integrated full balanced basic circuit blocks constructed by CC Ⅱ s, MOSFETs and capacitors are proposed in the paper.A second-order full balanced filter constructed by the circuit blocks is designed and simulated with the SPICE program. The simulation results agree well with the design parameters and show the fact that this kind of filter can operate in higher freqency than operational amplifier based filer.关键词：active filter;circuit theory and design;Current conveyor2|31|0更新时间：2025-12-08
- 摘要：华南理工大学电子与通信工程系Ｄｅｐｔ．ｏｆＥｌｅｃｔｒｏｎｉｃ＆ＣｏｍｍｕｎｉｃａｔｉｏｎＥｎｇｉｎｅｅｒｉｎｇＨｕａｎａｎＵｎｉｖｅｒｓｉｔｙｏｆＳｃｉｅｎｃｅａｎｄＴｅｃｈｎｏｌｏｇｙ华南理工大学电子与通信工程系是由原无线电工程系及国家教委批准的...2|37|0更新时间：2025-12-08
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