最新刊期
卷 28 ， 期 12 ， 2000
- 摘要：In the multi-path communication scenario,it is needed to estimate the two-dimensional angles and relative time delays of each multi-path ray.We have derived a method based on DOA Matrix for the estimation of these parameters from the estimated channel impulse response,using knowledge of the transmitted pulse shape function.Compared with the multi-dimensional MUSIC-like or ESPRIT-like ones,the algorithm doses not need any search.It is a closed form solution,so it has slight computation burden.关键词：two-dimensional angles;relative time delay;joint angle and delay estimation4|1087|3更新时间：2025-07-16
- 摘要：The effects of residual cubic phase error induced by Chirp Scaling algorithm on SAR image qualities are analyzed,and an SC-Chirp Scaling imaging algorithm for high resolution spaceborne SAR based on nonlinear FM filter is proposed in this paper.Squint equivalent range model is used,and a nonlinear FM filter method is applied to achieve cubic phase error correction in the algorithm.Computer simulation results are presented,which illustrate the algorithm having the capability to acquire evident improvement of high resolution spaceborne SAR image qualities.关键词：spaceborne synthetic aperture radar;chirp scaling algorithm;radar imaging;nonlinear FM filter2|766|0更新时间：2025-07-16
- 摘要：In high-speed wide-band digitizer at high sweep speeds,only a few samples of the signals can be on screen.To give the user a reasonable view of the signals and measure their parameters accurately,interpolation is necessary.In this paper,the digital interpolation theory and the structure of interpolation multiphase filter are studied based on digital signal processing,and the algorithm of sinc interpolation is derived.At last,the computer simulation examples and RMS errors are given.关键词：high-speed sampling;interpolation theory;sinc interpolation algorithm;simulation2|3278|4更新时间：2025-07-16
- 摘要：According to airborne SAR imaging requirement we define the minimum ratio of alias' energy,which will overlap into passband after desampling,to passband energy as the proper criterion for the design of the desampling filter of the SAR real-time imaging system.After developing Lagrange multiplier algorithm,we provide steps to obtain the optimal desampling FIR filter.With comparing two filters,one takes account effect of the antenna radiation pattern and the other doesn't.We conclude that it is necessary to design a specific desampling filter that includes the effect of the radiation pattern of the antenna.关键词：desampling FIR filter;Lagrange multiplier algorithm;airborne SAR real-time imaging system2|961|2更新时间：2025-07-16
- 摘要：The concept of transverse polarization filtering is presented under the high-resolution radar system.Radar signal detection is studied via this concept.Detection results are satisfactory.Function relationships between detection characteristics and parameters of transverse polarization filter group are given.It is proved that the optimization of radar detection characteristics in polarization domain may be eventually abstracted as a SINR polarization filtering problem.关键词：polarization;high-resolution;signal detection;transverse polarization filtering2|1157|5更新时间：2025-07-16
- 摘要：Registration of EEG to MRI is an effective way to obtain both high spatial and high temporal resolutions in functional brain imaging.There are two common methods in the registration:fiducial points based matching and surface based matching.The matching based on fiducial points has the difficulties in locating and measuring of fiducial points accurately.Meanwhile,in surface matching,the scalp must be scanned by a high spatial resolution equipment.The aim of this study is to investigate a weighted combination method using electrodes and fiducial points.Simulation results show the effectiveness of the new method.Also,the new weighted combination method has better registration accuracy than that of fiducial points or surface matching using electrodes respectively.关键词：EEG;MRI;registration;matching2|965|0更新时间：2025-07-16
- 摘要：The method of ranging tracking using wavelet transform in high-resolution radar system is researched in this paper.The back-scattered power of the target is represented as a function of time.The range of the each scattered point could be measured as a delay time of transmitter pulse.But for moving targets the amplitude and range would change speedily.So it is very difficult to tracking the range.In this paper the method of wavelet transform of input pulse for range tracking system is satisfactorily demonstrated.关键词：range tracking;signal processing;wavelet transform;high-range resolution radar2|932|0更新时间：2025-07-16
- 摘要：Exact calibration of radar systems is an important problem to ensure the data reliability of the terrain and sea clutter measurement.This technique calibrates the L-band HH polarized airborne clutter measurement radar absolutely with active radar calibration (ARC) on the ground.The effects of background clutter,airplane postures and GPS errors on system constant,time delay and antenna pattern are considered carefully by means of design of RCS,signal extraction of ARC and a set of coordinate transforms.The validity of this method is proved by the analysis results.关键词：clutter;radar;calibration;airborne;measurement2|1006|0更新时间：2025-07-16
- 摘要：This paper discussed the technique of self-adjustment for focusing field emission arrays (FFEA).This method made etch gate and focus electrode in FEA very precise for fabrication of Spindt type FFEA.The difference between traditional way and self-adjustment way is pointed in the paper.For ensuring that the hole of focus electrode is precisely made,we developed transparent resistor layer with Ni-SiO2.A typical device has been developed,with focus electrode made by the technique of self-adjustment.关键词：self-adjustment;focusing electrode;double-gate focusing;focusing FEA2|831|0更新时间：2025-07-16
- 摘要：A new moving target detection method for forward-looking airborne radars is presented.Theoretical analysis and computer simulation are performed.The result shows that the moving target detection method can work well with the condition that the estimation accuracy of the radar carrier moving parameters is lower,and is feasible in the engineering.Finally the detection performance of the method with various errors is presented.关键词：moving target detection;forwarding looking airborne radar;SAR2|1021|1更新时间：2025-07-16
- 摘要：Modulated stepped frequency radar is a system to get high-resolution range profile with the problem of redundancy.So extracting method is presented to eliminate such redundancy and get the true position of target.In this radar system,target motion is the main factor to influence its performance.Characteristics of extracting method are analyzed here,so do the effects of velocity and velocity estimated error on this method.In order to overcome the influence of return pulse motion,an improved extracting method is provided.The capability of this improved method is good with accurate velocity estimation,but decreases with increasing velocity estimated error.The velocity estimated error limit is addressed to reduce the problem caused by it as far as possible.In addition,an amplitude interpolating method is given to resolve the range-coupling shift caused by velocity estimated error.The emulated computer results validate the correctness of theory analysis.These two suggested methods,especially the later amplitude interpolating method,can settle the key problems of target moving in the signal processing of modulated stepped frequency radar and provide foundation for realization of such radar system.关键词：modulated stepped frequency;high-resolution range;moving target3|1815|6更新时间：2025-07-16
- 摘要：This paper reports the theoretical study on the transmission efficiency,bandwidth and frequency shift of anomalous dispersion atomic optical filter with off-axis incident beam.The experimental transmission spectrum of anomalous dispersion atomic optical filter with off-axis incident beam is given in this paper,which agrees well with the theoretical result.The results will give the theoretical foundation for the use of anomalous dispersion atomic optical filter in a wide field-of-view acquisition approach of inter-satellite or free space laser communications,which will be propitious to the pointing and acquisition in free space.关键词：anomalous dispersion atomic optical filter;off-axis incidence;transmission spectrum2|860|2更新时间：2025-07-16
- 摘要：This paper propose an evolutionary robot behavior algorithm which is based on developmental network.The new algorithm use nature selection to evolve neural network and can autonomously avoid obstacles,move,reproduce and attack.A simulation environment is developed to test the new algorithm.The experimental results demonstrate that the developed system is well suited to long-term incremental evolution and original behaviors evolution.关键词：natural selection;developmental network;L-system;evolutionary algorithm;original behavior3|1143|1更新时间：2025-07-16
- 摘要：A fast data association algorithm based on the attribute intensity of space intersection for the static association problem is presented in this paper.All of sensors are passive sensors,which obtained the angle only in presence of clutter,missed detection,false alarm,and an unknown number and location of targets.Comparison of our method to the classical algorithm demonstrates that our algorithm is superior to the classical approach in terms of computational complexity and association accuracy via several simulations.关键词：multitarget-multisensor tracking;data association;passive sensor2|922|13更新时间：2025-07-16
- 摘要：It is significant to increase the precision of reference voltages produced by the reference resistor ladder at the front-end of high-speed A/D converters.To suppress nonlinear errors caused by the loading effect on the resistor ladder,a kind of parallel resistor ladder with fewer resistors on each branch is proposed.The error distribution of reference voltages along the parallel resistor ladder is also given.Without any compensation circuit,obvious precision improvement of reference voltages is achieved in addition to another advantages of faster settling speed、strengthened driving capability and lower temperature sensitivity.Both detailed analysis and simulation results show that it is very suitable for the use in high-speed A/D converters such as flash、multi-step and folding architectures,etc.关键词：reference resistor ladder;loading effect;A/D Converter2|864|1更新时间：2025-07-16
- 摘要：This research addressed an urban traffic intelligent control system,which adopts a multi-agents coordination in urban traffic control to coordinate the signal of adjacent intersections for eliminating the congestion of traffic network.An agent represents a signal intersection control,and multi-agents realize coordination of multiple intersections to eliminate congestion.Based on Recursive Modeling Method and Bayesian learning that enables an agent to select his rational action by examining with other agents by modeling their decision making in conjunction with dynamic belief update.Based on this method,a simplified multi-agent traffic control system is established and the results demonstrate its effectiveness.It is very important for ITS.关键词：multi-agent;cooperative control;urban traffic control;ITS7|2863|6更新时间：2025-07-16
- 摘要：Key issue of weak moving targets detection under lower signal noise ratio is managing to enhance the target echo energy using long time coherent integration.During integration the target may migrate from one to another across radar range and Doppler resolution cells,motion compensation should be taken into consideration to improve detector's performance.Based upon dwelling mode of radar beam in phased array radar system,this paper presents a novel detection framework which using range stretching and joint time frequency processing to fight against the case where range and Doppler cells of echoes migration is presented.A possible realization diagram of such a detector is suggested and performance analysis is given.Simulation results and experiments on real data confirm the effectiveness of this method.关键词：weak target detection;range migration;Doppler migration;motion compensation2|1777|31更新时间：2025-07-16
- 摘要：On the basis of theory and model on high-resolution radar target polarization detection Presented in reference,and via the wide-band polarimetric scattering data of a stealth plane and a fighter as well as clutter models,simulation experiments on high-resolution polarization detection in two characteristic cases are performed.Results are given to verify conclusions of reference[1].关键词：high-resolution;polarization;Target Detection;transverse polarization filtering2|1019|1更新时间：2025-07-16
- 摘要：In this paper,the role of smart antenna in future mobile communication system is introduced.We introduced multibeam and adaptive array antenna,giving the definition and structure.The spatial and temporal communication theory,spatial and temporal channel model and space-time signal model are emphasized,the algorithms in smart antennas are compared.Finally application prospect and difficulties are discussed.关键词：smart antenna;mobile communication system;digital beam forming2|1778|7更新时间：2025-07-16
- 摘要：In this paper,inspired by Jelonek's algorithm,an improved attributes reduction algorithm is given based on the approximation quality of a single attribute and the modified discernibility matrix due to Hu.It is shown that the presented algorithm is of lower computational complexity than Jelonek's algorithm.关键词：rough set;approximation quality;reduction of attribute;discernibility matrix2|1452|68更新时间：2025-07-16
- 摘要：A cost function based on third- order cumulants is presented,and then a lattice adaptive filtering algorithm is proposed by minimizing this cost function.The computer simulation results for linear prediction are also given to demonstrate the correctness and effectiveness of the proposed adaptive algorithm.关键词：higher-order statistics;adaptive filtering;lattice algorithm2|963|0更新时间：2025-07-16
- 摘要：In order to inprove the tracking performances of some sensors and local nodes,the paper discusses the state estimation techniques in multilevel multisensor surveillance systems with feedback information.Based on the single sensor Kalman fitering equations with feedback information,this paper presents two-level centralized,distributed and hybrid track level fusion methods with feedback information in multicoordinate systems.In the different Cartesian coordinates,several kinds of track level fusion methods with feedback information for three-level multisensor data fusion systems are proposed,in which centralized-distributed,distrbuted-distributed and hybrid-distributed estimation combination problems with feedback information are considered,and proves that two kinds of three-level estimation solutions with or without feedback information are optimal and equivalent in the form of the theorem.The simulation results show that the multilevel multisensor data fusion system can not only increase the global estimation acuracy of target but also greatly improve the tracking perfomances of some sensors and local nodes by using the feedback information.关键词：data fusion;hierarchical estimation;feedback mechanism;multisensor tracking;track fusion2|1144|7更新时间：2025-07-16
- 摘要：By using a new blind beamforming method proposed in this paper rather than resorting to multidimensional spectra searching,we get an algorithm for DOA estimation of distributed signals.It needs little prior knowledge about the distribution function of the source and can be applied in nonuniform array condition.The simulation studies show that the new method outperforms conventional MUSIC algorithm by reducing the sensitivity for scenarios with distributed sources.关键词：distributed source;DOA estimation;blind beamforming2|868|3更新时间：2025-07-16
- 摘要：Based on the 2-D model,the case of DOA estimation in presence of complicated noise is studied in this paper.Focusing on the cyclostationary signal,widely existed in practice,a new method using cyclic statistics is proposed.It is the insensitivity to any stationary additive and multiplicative noise that makes it more practical.关键词：complicated noise;cyclostationary;DOA estimation2|1222|0更新时间：2025-07-16
- 摘要：In this paper we discuss several important complexity algorithms for time series,such as Kolmogorov Complexity (KC) and C1、C2 complexity .Had analyzed these methods,we bring forward a new complexity measure:partition complexity.The new arithmetic overcomes the disadvantage of those older methods.It sufficiently reflects its advantage through clinic tests.关键词：time series;complexity measures;partition complexity2|1015|3更新时间：2025-07-16
- 摘要：Ambiguity is a inherent matter of PD (pulse Doppler) radar.The Sunzi algorithm and the cluster algorithm are two popular algorithms for ambiguity resolution.In this paper,a new ambiguity resolution algorithm ,i.e.group algorithm,is proposed.The new algorithm has better performance than the Sunzi algorithm because it can rectify the measurement error and can resolve Doppler ambiguity as well as range ambiguity.And thanks for the use of look-up table,the group algorithm fits real time signal processing better than the cluster algorithm.关键词：radar;frequency estimation;ambiguity resolution3|2976|14更新时间：2025-07-16
- 摘要：Using two-wave theory the start oscillation currents of backward-wave oscillations(BWO) with three kinds of typical practical non-homogeneous output circuits are analyzed and some corresponding conclusions are made.The results are applicable not only in weakly tapered circuits but also in those strongly tapered circuits.Furthermore some important principles for the design of high-power traveling-wave tubes are given.关键词：traveling-wave tube;backward-wave;start oscillation current2|1044|2更新时间：2025-07-16
- 摘要：A stable resistance-free current-fed modeling and a stable resistive one are presented respectively in this paper.The former is simple in implementation and high in computational accuracy.The latter overcomes the disadvantage that the former is unsuitable for the analysis of the electromagnetic problems with the almost lossless resonant structures and further reduce computational time needed as the internal resistance suitably rises.关键词：the finite-difference time-domain (FDTD) method;current-fed modeling;stability;computational accuracy2|909|0更新时间：2025-07-16
- 摘要：The theoretical analysis of aperture synthesis in the along-track direction of a synthetic aperture radiometer is presented under the theory of convolution.The baseline design is accomplished according to a spatial frequency domain analysis.The brightness temperature of the earth in the along-track direction is reconstructed by two numerical approaches,i.e.the method of moment and the linear algorithm based on the Backus-Gilbert theory.Numerical simulated test cases show that the reconstruction of the brightness temperature agrees well with the original on the base that the antenna array is effectively thinned in the along-track direction.关键词：microwave radiometer;synthetic aperture;reconstruction algorithm2|1070|4更新时间：2025-07-16
- 摘要：In this paper,a new algorithm,periodic/Anisotropic PML B.C.for periodic FDTD calculation,is introduced.The result show that the new method is better in precision than the old one and eliminate the shortcoming in the old.This work makes periodic FDTD method more convenient and accurate in use.关键词：periodic structures;FDTD;boundary condition2|2380|0更新时间：2025-07-16
- 摘要：A new similarity method in FEM is presented for researching of the problems about the nonuniform and irregular region,such as micromachined microwave coplanar waveguide,which can be fabricated through a commercial CMOS process.By using this new method,we calculate the characteristic impedance of this kind of suspended waveguide and analyze the change with its dimensions.From the result,we summarize the different structures with characteristic impedance of 35Ω、50Ω、75Ω、120Ω.关键词：micromachined coplanar transmission;characteristic impedance;FEM method;similarity discretization2|975|2更新时间：2025-07-16
- 摘要：This paper introduces a contrast-based multiresolution image fusion technique.Three steps can implement the method: First,the input multispectral images are decomposed by wavelet transform,meanwhile,the multiresolution contrast sequences of each input images can be obtained.Second,according to the contrast-based criterion,the multiresolution analysis of the fused image can be obtained on the corresponding levels of the multiresolution analysis of the input images.Finally,the output image can be obtained through inverse wavelet transform.This algorithm is tested by fusing the visual and infrared images from same scence.The experiment shows that the fused image can preserve the details of the each input images successfully.关键词：image fusion;wavelet transform;multiresolution analysis;image processing2|2146|56更新时间：2025-07-16
- 摘要：The power loss of deflection yoke is analyzed.Hystersis loss is the main part of power loss of deflection core at the driving condition.Hystersis loss and heat distribution can be calculated by means of MSC/EMAS,MSC/NASTRAN and DUEMAS.The calculation method and temperature rising caused by hysteresis loss are introduced in this paper.关键词：hysteresis loss;deflection;heat distribution2|1296|0更新时间：2025-07-16
- 摘要：A rotated covariance extended Kalman filter algorithm which is very useful for emitter passive localization and tracking is presented in this paper.The rotation transformation on covariance matrix of extended Kalman filter subtly handles the nonlinear problem in stochastic estimation problems with simplicity.In this paper,principle of rotated covariance is derived first,then detailed algorithms for 2D passive localization are developed.Experimental results show that the proposed algorithm is better than those linearization by differentiation-based extended Kalman filter and universal linearization concept-based extended Kalman filter.关键词：passive localization;passive tracking;EKF;rotation of covariance matrix2|1136|1更新时间：2025-07-16
- 摘要：The finite-length multi-layer dielectric cylinder is used to model the trunk.The electromagnetic scattering model for adjacent trunks and sphere above a rough surface ground plane is analyzed by using the reciprocity theorem.The validity of the method is checked by numerical computations based on the moment method.The influence of randomly distributed trunk on the scattering pattern of sphere is discussed at L,C and X bands.It is shown that the low frequency can be used for the purpose of target detection buried in a discrete random media.关键词：reciprocity theorem;electromagnetic scattering for finite-length multilayer dielectric cylinder;sphere scattering;rough surface ground plane2|812|0更新时间：2025-07-16
- 摘要：Epitaxial YBCO(YBa2Cu3Oy) thin film of large area sized at Φ30mm-3 inch are deposited at the same time on LaAlO3 and sapphire substrates by inverted cylindrical opposited target sputtering technology (ICP).These films show the values of TC0=88~91K,JC=1~5×106A/cm2,RS(77K,145GHz)=20~40mΩ.The homogeneity of film at any side and reproducibility of film at both sides are good enough,to be applicable in microwave devices.关键词：superconductor;YBCO;thin film2|873|0更新时间：2025-07-16
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