二维离散系统的频域稳定性检验定理

本文提出的二维离散系统的频域稳定性检验定理可用于任意阶次的二维离散系统稳定性检验，本文定理的检验算法可避免环路积分从而减少了计算量提高了检验精度。     

因果移序定理及其应用

本文给出了因果移序定理的时域、z域和状态方程表达式，证明了因果移序定理在离散系统的时域、z域和状态方程分析中的重要地位和作用。这些表达式不但使得系统分析简捷清晰，而且物理概念清楚。各章之间的内在联系也可交待清楚，这十分有利于学生的理解和消化。我们历年的“信号与系统”的教学实践有力地证明了这一点。     

顺序触摸式开关

４６７．顺序触摸式开关该触摸开关的基础是一个具有保持接触的施密特（Ｓｃｈｍｉｔｔ）触发器，它由ＩＣ＿ｌａ、ＩＣ＿ｌｂ和Ｒ＿３构成。ＩＣ＿ｌｂ的输出通过Ｒ＿３反馈至ＩＣ＿ｌａ，这将导致两个选通门都保持其稳定状态。只要电路处于静态，即Ｄ＿１的阳极为低电位...     

关于前馈多层神经网络多维函数逼近能力的一个定理

本文首次证明了前馈神经网络多维函数逼近能力的一个重要定理，当隐层神经数目足够多时，其多维函数逼近能力与维数无关，也就是说我们只需研究其一维函数逼近能力，所得的结论完全适合于多维情形，该定量大大简化了前馈多层神经网络函数逼近问题的分析难度，本文还给出了该定理的一个应用。     

不确定系统的椭圆区域极点配置

本文应用线性矩阵不等式方法（LMIs）给出了椭圆区域的LMIs表示形式，研究了不确定连续和离散系统的区域极点配置问题，讨论了使闭环系统的所有极点配置在给定的椭圆区域的充分必要条件。所给的定理推广了基于圆盘区域的极点配置问题，最后通过实例仿真验证了该定理的有效性。     

一种新型移相级联式高压变频器

本文介绍了移相级联式高压变频器的结构、特点。这种高压变频器所用功率器件少，负荷均衡，输入输出线性度好，具有良好的控制特性。     

色散缓变光纤中Raman孤子自频移效应的研究

利用绝热扰动法研究了色散缓变光纤中Ｒａｍａｎ孤子自频移效应，得到了色散缓变光纤中Ｒａｍａｎ孤子自频移的表达式。结果表明：光纤色散变化率存在一个可以有效抑制孤子自频移的阈值，当光纤色散变化率大于这个阈值时，色散缓变光纤可以抑制孤子自频移，而当光纤色散变化率小于这个阈值时，色散缓变光纤不仅不能抑制孤子自频移，反而加剧孤子自频移。     

逻辑电平测试器

４９４逻辑电平测试器测试器是一种７段共阴极显示，它的输出是逻辑‘１’（显示Ｈ）或是逻辑‘０’（显示Ｌ）。未确定的电平显示为‘ｎ’。当输入为低电平时，Ｔ＿１被截止，Ｔ＿２和Ｔ＿３被导通。其结果在ＩＣ＿（ｌａ）有高的输出而ＩＣ＿（ｌｂ）为低输出，程序段‘...     

关于前馈多层神经网络多维函数逼近能力的一个定理

本文首次证明了前馈神经网络多维函数逼近能力的一个重要定理:当隐层神经元数目足够多时,其多维函数逼近能力与维数无关.也就是说我们只需研究其一维函数逼近能力,所得的结论完全适合于多维情形,该定理大大简化了前馈多层神经网络函数逼近问题的分析难度。本文还给出了该定理的一个应用。     

色散缓变光纤中Raman弧子自频移效应的研究

利用绝热优动法研究了色散缓变光纤中Ｒａｍａｎ弧了自频移效应，得到了色散缓变光纤中Ｒａｍａｎ弧子自频移的表达式。结果表明：光纤色散变化率存在一个可以有效抑制弧子自频移的阈值，当光经行色散变化率大于这个阈值时，色散缓变光纤可以抑制弧子自频移，而当光经行色散变化率小于这个阈值时，色散缓变光纤不仅不能抑制弧子自频移，反而加剧弧子自频移。     

On the stability preserving property of the double bilinear transformation on a class of 2-D transfer functions

This paper addresses the BIBO (bounded-input bounded-output) stability of a class of discrete 2-D quarter-plane filters in the presence of nonessential singularities of the second kind (NSSK's) on the unit bidisk. Conditions under which the double bilinear transformation (DBT) preserves stability are derived. The results presented here also extend the class of systems whose stability can be predicted. Use of the inverse DBT to produce a continuous equivalent of the discrete 2-D transfer function allows easy application of a continuous-domain equivalent of a criterion developed by Dautov. The necessary and sufficient condition for stability derived in this work provides a simple check for the class of systems under consideration. From this class of systems, it is also possible to construct stable pairs of mutually inverse transfer functions.     

On an inviable approach for derivation of 2-D stability tests

A tabular stability test for two-dimensional (2-D) discrete systems that was published in these Transaction is shown to be not correct. It is also shown that the claimed new method that it introduced to extend stability conditions from one-dimensional (1-D) to 2-D systems relies on a mathematically inviable argument. The paper tries to find a similar but correct algorithm and stability conditions. The outcome of the search after a stability test with similar algorithm is a variant of the Maria-Fahmy 2-D stability test for which a more concise set of necessary and sufficient conditions for stability are obtained. The search after stability conditions of similar appearance that can be posed on the correct algorithm, yields new necessary conditions for 2-D stability that resemble stability conditions associated with the "reflection coefficient" parameters in the 1-D Schur test.     

Robustness and stability properties of first order multi-dimensional (m-D) discrete processes

In this article, special properties of m-D first order discrete recursive processes are discussed. The results are interpreted in view of the well-known results of 1-D processes and their significance within the general theory of m-D systems is highlighted. In particular it is demonstrated that first order m-D processes share the same properties as 1-D first order processes in many aspects. This includes robustness against nonlinear effects and shift-varying conditions as well as stability under zero and non-zero input conditions, the effect of spectral transformations and the dynamic behavior in the space- (time-) domain. It is shown that the results in the 1-D theory follow from the developed m-D theory by formally settingm=1. This pertains to the closed form representation of the impulse response, the robustness properties and the stability conditions.     

Asymptotic Stability of a Class of Linear Discrete Systems with Multiple Independent Variables

This paper investigates the problem of asymptotic stability for a class of linear shift-invariant discrete systems with multiple independent variables. We establish the equivalence of this problem and that of robust stability for a class of ordinary linear shiftvarying discrete systems with the matrix uncertainty set defined by the coefficient matrices of the original system. On the basis of this equivalence, by using the variational method and Lyapunovs second method, necessary and sufficient conditions for asymptotic stability are obtained in different forms for the class of systems considered. The parametric classes of Lyapunov functions which define the necessary and sufficient conditions of asymptotic stability are determined. We use the piecewise linear polyhedral Lyapunov functions of the infinity vector norm type to derive an algebraic criterion for asymptotic stability of the given class of discrete systems in the form of solvability conditions of a set of matrix equations. A simple sufficient condition of asymptotic stability is also obtained which becomes necessary and sufficient for several special cases of the discrete systems under consideration.     

The Stabilizability and Connections between Internal and BIBO Stability of 2-D Singular Systems

The problem of stabilizability of 2-D singular systems is considered, a necessary and sufficient condition in terms of the existence of a polynomial solution to a Bezout identity has been generalized from 2-D regular systems to the singular case. The BIBO stability condition has been extended to 2-D singular systems. The detectability of 2-D singular system is further discussed, an equivalent condition is obtained. At last it is shown that 2-D singular system is internally stable if and only if it is BIBO stable, detectable and stabilizable.     

Stability of 2-D systems described by the Fornasini-Marchesini first model

A sufficient condition for the stability of linear two-dimensional (2-D) systems described by the Fornasini-Marchesini (1976) first model is presented. The condition is compared with previously reported conditions.     

Stability for two-dimensional singular discrete systems described by general model

This paper discusses the problem of stability for linear discrete 2-D singular general models (2-D SGM). A sufficient condition for the internally stability of the 2-D SGM is derived in terms of linear matrix inequalities (LMIs).     

Linear third-order discrete system stability under parameter variations

The letter presents a necessary and sufficient condition for the stability of discrete systems up to third-order under parameter variations.