最新刊期
卷 ， 期 9 ， 1995
- 摘要：A designing technique of2-D separable multi-step amplitude quantization low sidelobe aperture distribution with exponent retraint for airborne solid-state active phased arrays is proposed.It is shown that this method is effective to reduce the peak sidelobe levels in horizatical plane and other areas and the kind of T/R modules. Using 2-D separable design idea,the kind of column feeding networks can be greatly reduced in engineering application. The computer simulated results confirm the theoretical analysis.关键词：Solid-state active phased array antenna;low sidelobe;Aperture design;Amplitude and phase tolerance2|63|0更新时间：2025-12-08
- 摘要：In this paper, first some errors in derivation of the correspondenceless approach of quadric curve based stereo are corrected; and its existence of the solution for the reconstruction of curve are addressed. Subsequently in order to determine a unique solution, we propose a unique matching theorem using a trinocular vision setup. Finally some experiments with scenes of mechanical parts are described. It is demonstrated that planar curve objects can be reconstructed completely, correctly and quickly by using our approach.关键词：Curve based stereo;3-D reconstruction;Correspondenceless stereo;Quadric curve matching4|108|2更新时间：2025-12-08
- 摘要：This paper mainly discusses the speech enhancement algorithm based on the Minimum Mean Square Error（MMSE） estimation of speech short time spectrum. On the basis of the general MMSE estimation, a new algorithm using interframe frequency domain distribution constraint in MMSE estimation is proposed,if takes into account the correlations between interframe spectrum and incorporates them into the estimation.Due to the fact that the distribution of speech spectrum is unknown, two solutions are adopted: Gaussian distribution assumption and statistic approximation obtained by real speechmaterials.The new algorithm has been evaluated in our speech enhancement experimental system, and compared with other algorithms. The results show that the new algorithm is more effective to reduce the background noise without significant speech degradation.关键词：speech signal processing;speech enhancement;Short time spectrum extimation;noise suppression2|157|13更新时间：2025-12-08
- 摘要：This paper mainly deals with a new mode of SAR imaging, which is the imaging of moving objects in SAR. Based on the analyses of echo spectrum and joint time-frequence processing method,a new approach is presented to get the exact parameter estimation of slowly moving targets.It provides an efficient way for SAR imaging with combined AMTI. The computer simulation verifies its avaliability.关键词：Synthetic aperture radars;Imaging of moving targets;Time-frequence distrbution2|236|11更新时间：2025-12-08
- 摘要：This paper presents analyses of the clutter correlation matrix, optimal improvement factor and effects of parameters of an airborne radar displaced phase center antenna（DPCA） system.关键词：airborne radar;MTI;Displaced phase center antenna2|123|10更新时间：2025-12-08
- 摘要：The ISAR（Inverse Synthetic Aperture Radar）echo of a object flying in orbit is simulated by computing the backscattering fields of the object. The simulating and imaging process is discussed and the simulated images with the echoes are presented. In addition, the required PRF and needed coherent accumulating time for the imaging radar is also investigated.关键词：ISAR （Inverse Synthetic Aperture Radar）;Computing of the backscattering fields;Radar echo simulation;Imaging of the target in orbit2|150|12更新时间：2025-12-08
- 摘要：Based on the generalized Lorentz-Mie theory（GLMT）, the incident fundamental Gaussian beam is expanded in terms of the vector spherical harmonics. The interaction of Gaussian beam with a multi Lagered sphere located on the propagation axis is analyzed. The modified algorithm for wave beam parameter gn and the recursive formulas as well as the computing procedure to calculate scattering coefficients an and bn are proposed. And the numerrical results are discussed and compared.关键词：Gaussian Beam;Generalized Lorenz-Mie theory;electromagnetic scattering2|349|37更新时间：2025-12-08
- 摘要：The copy method which suits to three kinds of ordering Chrestenson function sequences is presented. Moreover the copy process is mathematically analyzed. And in copy theory this method is exactly the translational copy method while Chrestenson functions degenerate into Walsh functions is also explained in this paper.关键词：Chrestenson function sequence;Walsh function sequence;Orthogonal function;Multi-value logic2|35|1更新时间：2025-12-08
- 摘要：Mathieu functions are frequently encountered in many radiation,scattering and guided wave problems, which are formulated in the elliptic cylindrical coordinate system. Mathieu functions are also used in the studies of the elliptic optical fibre waveguides. Consequently their accurate computation is of general importance. A program flowchart for the computation of Mathieu functions and modified Mathieu functions of the first and second kinds,and some useful expressions for numerical computation are presented,and the related algorithms are discussed. Moreover,some typical tabulated data of Mathieu functions of orders up to 12 with positive and negative parameters q are given to eight significant figures.关键词：Mathieu functions;Modified Mathieu functions;Characteristic value2|368|13更新时间：2025-12-08
- 摘要：In this paper, by means of finding the solutions of Maxwell’s equitions which have a tensor dielectric permittivity,the wave equitions were obtained in rotation dielectric under the condition of longitudinal direct current magnetic field. The concept of twin scalar quantity waves was put forward because electric waves and magnetic waves are coupled each other,and it was proved that the scalar quantity waves meet Helmholtz equition. By means of finding the solutions of Helmholtz equition in cylindrical coordinates, the expressions of the scalar quantity waves, propagation constants, eigenvalue equitions and the expressions of field components were obtained,and the rotation character was discussed in a rotation optical fiber.关键词：Tensor dielectric permittivity;Maxwell’s equitions;Helmholtz equition;Twin scalar quantity waves;Rotation optical fiber3|81|4更新时间：2025-12-08
- 摘要：A novel multiwaveguide system which is a sectorial waveguide-gap structure for gyromagnetron （cusptron） is presented. The characteristic equation and stored energy expression of this structure are derived. The relationships of stored energy and efficiency with its dimensions and the results of large signal calculation are given. The obtained curves provide the theoretical basis for designing this kind of structure.关键词：Multiwaveguide;Sectorial waveguide-gap;RF system;Gyromagnetron2|34|0更新时间：2025-12-08
- 摘要：The analytic method for solving interval linear equations is improved to meet the demands of circuit worst-case tolerance analysis. Based on the improved method ,fast algorithm and exact algorithm are given for steady-state tolerance analysis. By utilizing the relationship between timedomain analysis and frequency-domain analysis, the method for circuit dynamic-state tolerance analysis is given too. The proposed methods’ advantages lie in their efficiency, practicability and potentialities.关键词：Circuit tolerance analysis;Interval arithmetic method2|108|10更新时间：2025-12-08
- 摘要：The DCT frequency spectrum features of image edges are analyzed theoretically and illustrated by numerical examples. It is proved that for a image subblock with a single straight edge, the DCT coefficient. energy compaction orientation and the spatial edge orientation are not always orthogonal. With this result applied to transform coding,a classification technique based on the frequency spectrum features of edges is put forward. Experiments show that this classification technique is effective.关键词：Image edge;Spectrum feature;Subblock classificatoin;Transform coding2|94|6更新时间：2025-12-08
- 摘要：VSAT is one of primary trends of future satellite communications. Most of recent VSAT system are used as a data network or a voice network in which data can be transfered in voice channels. Such a system can not give a higher effieiency of channel utility and perform a voice/data integration well. The performance of SALOHA for multichannel voice/data integration VSAT is discussed and the numerical results are obtained. It is concluded that the protocol can provide a higher throughput, lessen the voice acess delay effectively and coordinate the difference between voice and data. Under the heavy load of voice the data channel can be occupied by voice and a dynamic assigment algorithm of channel is acquired.关键词：VSAT satellite communication;voice/data integration;S-ALOHA2|39|0更新时间：2025-12-08
- 摘要：This paper presents the partial fundamental theory of the Fourier transform for the staggered perodic sequence. The time-varying property of staggered periodic FIR filter, the maximum system instantaneous response, and the relation amony the output sequence spectrum, the input sequence spectrum and the frequency response of filters are emphatically described.关键词：Nonuniform sampling in time domain;Spectrum anylysis;FIR filter;matched filter;Time-varying property.2|218|12更新时间：2025-12-08
- 摘要：The side fed H shaped antenna was fabricated using YBCO/YSZ syperconducting thin film. The relative efficiency of this superconducting antenna to the silver antenna is 9. 3dB in the x polarized direction and 13. 6dB in the y polarized direction（the input power is 10dBm）.关键词：High Tc superconductor;Side fed H shaped antenna;efficiency2|67|0更新时间：2025-12-08
- 摘要：The method of moments is employed in conjunction with the equivalent-source technique and the modal expansion theory to analyze the multigroove and multimode coaxial radiators. In the analysis no restriction is imposed on the number,width and depth of grooves, so that the theoretical method and the analitical formulation are applicable to the analysis and design of wide-ranging coaxially grooved radiators.关键词：Coaxial radiator;method of moments;Modal expansion theory2|35|1更新时间：2025-12-08
- 摘要：The time-domain integral equation technique is presented for computing the response of dielectric objects. Electromagnetic scattering results for sphere and sphere-capped cylinder were obtained by a given incident wave. The consistency with the measured respones in seen to be very good. Although the smooth objects with plane symmetry are considered in the examples, this method can be implemented for an object with arbitrary shape.关键词：Time-domain integral equation technique;Dielectric object;electromagnetic scattering4|81|1更新时间：2025-12-08
- 摘要：The mode-matching method is presented to obtain the discontinuity parameters and optimize the design of five-port waveguide junction. According to the simulation results, a five-port waveguide junction has been designed. The test results are correspondent with the calculated ones.关键词：Five-port junction;Reflection coefficient;Mode-matching method;Evanescent modes2|49|1更新时间：2025-12-08
- 摘要：Based on the space-time two dimensional signal processing, this paper proposes a method for the imaging of moving targets with SAR by using the equivalent space-time echoes of array antenna. This method,which is much more effective to detect and image the targets whose radial velocity is very small than a single antenna, has no blind area of velocity and can produce a high resolution image of slow moving targets. The computer simulation results illustrate its availability.关键词：Space-time two dimensional signal processing;array antenna;Synthetic aperture radars;Detecting of moving targets2|240|13更新时间：2025-12-08
- 摘要：A new kind of rectangular waveguide loaded with dielectric walls is presented, in which uniform field is propagated. Its parameters are obtained by numerical evaluation. Furthermore, the influence of treated materials is studied.关键词：Rectangular waveguide loaded with dielectric walls;Uniform field;Fundamental mode2|52|0更新时间：2025-12-08
- 摘要：A variational solution of waveguide junctions considering the wall losses on plates of transverse discontinuity is presented ,using the E-field matching techniques with enforcement of the conservation of complex power（CCPT）. For example,the discontinuity impedance of a coaxial line terminated in a circular waveguide is calculated and the stability of results is analyzed.关键词：Lossy model of waveguide junction;Conservation of complex power technique;Variational method.2|46|1更新时间：2025-12-08
- 摘要：The convergence of Learning Subspace Methods（LSM） for pattern recognition is studied. The transformed matrices of learning subspaces are proved to converge to the estimation of pattern autocorrelation matrix,thus the convergence of Kohonen’s self-supervised LSMs is proved. At the same time, the approximate expression of the eigen spectrum caused by LSM’s rotation and the upper bound disturbed theorem of Learning Subspace are presented.关键词：neural networks;Self-supervised;Learning subspace;pattern recognition;Distance measure;Transformed matrices;Eigen spectrum;disturbance2|152|3更新时间：2025-12-08
- 摘要：Vector quantization and color spatial quantization methods based on Kohonen Neural Network are presented. A palette and a codebook for color spatial quantization are obtained conveniently and efficiently by this means; Image compression techniques for digital aeronautical map must be chosen to allow rapid decompressionn and display, so a compression method based on palette technique is proposed here,which use the palette and the codebook as double look-up-tables while decompressing and displaying.关键词：Kohonen neural network;Palette;Color spatial quantization;compression;Decompression2|50|2更新时间：2025-12-08
- 摘要：This paper presents a three-dimensional image segmentaion method based on edge and fuzzy set theory. By using a Gauss-Laplacian operator,the edges of structures in the image are detected,then a region growing is applied to obtain the 3D binary mask of the volume of interest. From the Gauss-Laplacian image and the mask,the 3D fuzzy mask is determined and the volume of interest is then extracted.关键词：Image segmentation;fuzzy set;edge detection2|160|4更新时间：2025-12-08
- 摘要：The Morlet wavelet analysis is applied to analyze the time-frequency properties of electromanetic backscattered signals from targets. To improve the time and frequency resolution,we construct a related wavelet with instantaneous frequency that increases linearly with time,and make the scale increase properly. Compared with the conventional short-time Fourier transform and Wigner-Ville distribution, the numerical results show that the wavelet time-frequency analysis provides high time resolution in the early-time high frequency resolution in the late-time,and high detectivity in nolses.关键词：wavelet transform;time-frequency analysis;Object detecting2|167|11更新时间：2025-12-08
- 摘要：On the basis of the study of the maximum- likelihood estimation technique which elimilates the intersymbol interference, this paper presents a near-maximum-likelihcod estimation scheme which is used in the voiceband serial data transmission system. The scheme employs predecision feedback to reduce the number of the effective components of channel states and the simplified Viterbi algorithm,thus reducing the amount of operation. Simulation analysis indicates that the error performance of this scheme is superior to that of the decision feedback equalizer with the square root Kalman algorithm.关键词：signal detection;Detection technique;Short-wave communication;communication2|85|4更新时间：2025-12-08
- 摘要：In this paper,A new systematic model for access mode of "contention-collision cancellation" in LAN has been simply catalogued. The performance judgement ofr I type systematic model has also been finished. Then the simple and effective formulation M= N- 1/p + 1 is given.（M: the average number of customers;N :the source number of customers; P:the probability of each customer source for requesting service）.关键词：Contention-Collision Cancellation;LAN2|49|21更新时间：2025-12-08
- 摘要：A new algorithm for the fast computation of a 2-D discrete cosine transform（DCT） is presented. It is shown that the N×N DCT, where N=2m, can be computed using only N 1-D DCT’s,as in the conventional row-column approach. Hence the total number of multiplications for the proposed algorithm is only half of that required for the row-column approach,and is also less than that of most of other fast algorithms,while the number of additions is almost comparable to that of others.关键词：image processing;discrete cosine transform;fast algorithm2|158|0更新时间：2025-12-08
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- 摘要：应用ＳＡＷ卷积器捕获卫星定位通信系统的Ｑ－ＳＳ信号房少军，徐明（大连海事大学电子系，大连１１６０２４）－、引言两相扩频（Ｂ－ＳＳ）技术在卫星定位通信系统中得到了广泛应用。但是，如果在码分多址的卫星定位通信系统中采用Ｂ－ＳＳ信号，将会因卫星转发器的非线...2|39|1更新时间：2025-12-08
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