Two computationally efficient state-space structures for general 2-D digital systems described by Roesser s local state-space model are presented. Some properties of controllability and observability Gramians of the above two structures are derived. The overall roundoff noise model of 2-D digital systems implemented with fixed-point arithmetic is given. On the basis of the above theory, the low roundoff noise optimal state-space realizations of general 2-D digital systems are obtained. Finally, an example is given to demonstrate the differences of round- off noise arid computational efficiency between the above two structures.

Some new methods for reducing the multiplying noise in the digital images, which are mainly the one of weighting and adding methods, are proposed, after that the characteristics of the noise is studied. The theory is analysed with the common model of multiplying noise and proved by the experiments with real data. It is clear that these methods have more ad-Tantages than traditional ones in processing digital images.

A Homotopy continuation adaptive filtering algorithm is proposed in this paper. The algorithm introduces the homotopy continuation method into the IIR adaptive filtering, which may provide a high stability for IIR filter without any stability monitoring attached.

The 3-D motion parameters of object in space can be solved by using the 2-D optical flow and projection coordinates in image plane-This algorithm is linear, if the dimension of surface structure of motion object is smaller than the distance between the object and its projection image plane.

According to the next-state equations of various ternary flip-flops (tri-flop), which are based upon ternary modular algebra, various ternary flip flops are implemented by using universal-logic-module U_hs. Based on it, ternary sequential circuits are implemented by using array of universal-logic-module U_hs.

Generalized equivalent two-port measurement equations for reciprocal multiport network are presented, and problems using "mutual" equivalent parameters of the measured network in S-parameter measurements have been solved in this paper. This would shorten greatly measurement procedures for S-parameters and save a lot of measurement time. Experimental ex-ample is given.

The multi-layered media modeled by the Cantor bar are a type of fractal structures, which have been found wide applications in some optical areas, If they are introduced into microwave fields, a new kind of microwave devices will be developed. In this paper, the reflection properties of wave in a waveguide filled with fractal Cantor layers are investigated. Based on the self-similarity of networks, a new exact self-similar algorithm for reflection and transmission coefficients is derivel. Some examples are ...

The dispersion characteristics of a cylindrical dielectric waveguide with periodic metallic strips are analyzed by Galerkin s method. After obtaining the rigorous dispersion equation, the dispersion curves for both TE and TM modes are calculateld. The variations of the width of the stropband, the center frequency and the maximum attenuation constant in the stop-band with the metallic strip width are given. The convergence properties of numerical solution are also discussed.

The propagation matrix method of electromagnetic waves in stratified chiral media is introduced for the first time, and the general expressions of propagation matrix are derived. The reflection and transmission properties of electromagnetic waves at different chiral interfaces, one layer of chiral medium slab as well as air-chiral medium on metal substrate are analysed, in which the effects of chiralit admittance are considered especially.

In this paper, the basic theory of range-alignment in Inverse Synthetic Aperture Radar (ISAR) imaging is analysed. Two new methods of range-alignment are proposed. One is peak point alignment, and another is direct range-alignment. Based on the measurel radar data, the differences between the above-mentioned new methods and amplitude correlation method are liscussed, resulting in the confirmation on the superiority of the direct range-alignment method.

A new universal preprocessing method is proposed to estimate angles of arrival with high resolution, which is applicable to one- or two-dimensional high resolution processing based on arbitrary center-symmetric arrays (such as uniform linear arrays, equal-spaced rectangular planar arrays and symmetric circular arrays). By mapping the complex signal space into the real one. the new method can effectively off load computational amount needed in the signal subspace high resolution direction finding techniques ...

A new spectral estimation method based on the least mean square error of the forward linear prediction of AR model is introduced in this paper. The spectral estimation is obtained by the AR parameters estimated by the conjugate gradient method. The simulation results show that for this algorithm there is no bias in the frequency estimation, and the spectral line splitting is very week and the spectral resolution is high. The performance of spectral estimation. of the new method is similar to that of the Marple algorithm.

This paper develops a divided-step square root Kalman filtering theory based on the classical square root Kalman filtering and the gradient algorithm. Using these two algorithms, various simplified algorithms can be formed. Their computation time is much reduced, but their performances are not degraded remarkably. So, this filtering theory is mors adaptable for high-speed data transmission systems.

According to the quality of symmetrical sequence for S_BOS neighbouring logic, a general formula for determining the vertex subset of left and right bounds-of S_BOS bound sequence is given. A foundation of practical algorithm which can be used to select the bound range is provided for fast realizing S_BOS symmetrical sequence with the method of "search of bounce bound".

The imperfection in noise circ uit theory is discussed, and then a branch set spectral analysis method for electronic noise is given. It makes the accuracy and efficiency of noise calculation remarkably improved. Based on this method, a computer program for noise performance analysis and low noise design is made out. Einally, a computing example is given.

The basic idea of marching-on-in-frequency method is that the discretized integral equation is solved by using one of the iterative approaches, and the initial estimates are produced by using an extrapolation scheme based on error minimization. The iteration formula in the CST is corrected, which increases the convergence rate considerably at lower frequencies. It is important for convergence that the iteration is carried out in complex-frequency domain, because the matrix condition is improved and more accurate initial estimate can be obtained from the stner othly varying solutions in complex-frequency domain.

Multi-center cylindrical harmonic function expansion method is introduced for formulating the two-dimensional scattering problems in which the scattered fields are represented in an expansion terms of the cylindrical harmonic functions at some proper points. The boundary conditions are applied at the surface of the scatterer and are satisfied using point-matching. It is shown that the generalized multipole technique and the cylindrical harmonic function expansion method are two special cases of this method. The solution for the coef- ficients of the series are obtained by inversion of an overdetermined matrix equation by least square method.

It is described in this paper that the solar cells with ultra-high efficiency are proposed by A. Marks, which can convert 60-80% of the accepted sunlight into electric energy. The existed problems on his design scheme are analyzed, and the difficulties to carry out this design scheme and the directions of improvement are discussed. Although the solar cells fail to be manufactured now, but it is believed that they may be realized in the future.