几种离散正、余弦变换的卷积乘积关系

本文导出第Ⅰ、Ⅱ种奇、偶离散正、余弦变换的变换域乘积与时域卷积的严格关系,从而可用这些正弦族正交变换做数字滤波。     

离散时间傅里叶变换的教学探讨与设计

根据“理论联系实际”教学指导理念,本文梳理了离散时间傅里叶变换的基本概念、重要性质、典型应用等关键教学内容,设计了Matlab仿真作业的上机实践环节,将离散时间傅里叶变换理论和工程应用实践相挂钩。通过此类教学设计,强化离散时间傅里叶变换知识点的实践价值,深化实践应用,极大促进了学生对傅里叶变换知识点的消化吸收,提升了学生上机应用能力培养,取得了较好的教学效果。     

离散时间系统边界条件的确定准则

现用《信号与系统》教材中，有关离散时间系统数学模型──差分方程，其求解方法一般均先分别解出零输入响应和零状态响应而后合成全响应，很少涉及经典求解方法及如何正确地选取边界条件的问题。本文通过对离散时间系统在不同激励情况下的讨论，提出了经典求解法边界条件的确定准则和优化方法，以澄清学生在学习中的模糊认识，并作为现用教材的补充。     

基于数字移相的时间间隔测量网络时间统一优化

网络时间统一是采用网络时间授时方法实现对互联网时间同步和统一,保障授时系统的稳定运行。传统的网络时间统一方法采用的是网络时间协议和时间间隔均匀采用的时间统一方法,由于网络编码过程中产生同态误差,导致对时间统一性的跟踪性能不好。文章提出一种基于数字移相的时间间隔测量网络时间统一优化算法,构建了网络时间统一网络协议,采用信息编码方法进行网络时间的信息模型构建,基于数字移相的时间间隔测量方法,实现对网络时间统一算法的优化设计,仿真结果表明,该方法在实现网络时间统一中的优越性能,在提高网络授时统一性和可靠性方面具有重要的应用价值。     

离散时间系统中的噪声辅助信号传输

 基于一种平均信噪比讨论了离散时间系统中的三种典型噪声辅助信号传输的问题.仿真得到:当输入周期信号在阈下时,噪声能辅助信号的传输,随机谐振现象存在.存在一个噪声强度范围,其间系统的输出平均信噪比大于其输入平均信噪比,即输出输入平均信噪比增益大于1.随机谐振的功效随着系统阈值的增加,或噪声概率密度函数的拖尾变厚、零均值周边脉冲变窄而降低.这些结果同样说明了离散时间系统中随机谐振的复杂性,它的存在和功效也依赖于系统性能的测度和噪声类型.这些结果拓广了随机谐振在数字信号处理中的应用.     

一类离散时间系统的间接自适应模糊滑模控制

提出了适用于一类不确定离散时间系统的间接自适应模糊滑模控制策略。首先,根据指数趋近律得到离散滑模控制的理想控制律,然后,用两个模糊系统近似其中的未知函数,用第三个模糊系统近似切换控制。模糊系统的参数向量由带参数投影的自适应律在线调整。证明了该控制算法可以保证闭环系统状态有界,且跟踪误差收敛到原点的小邻域内。仿真结果在表明算法有效性的同时具备减轻振颤的能力。     

离散时间系统响应求解及其待定系数确定

响应求解是“信号与系统”课程教学中的核心内容.离散时间系统中方程右边有激励的移位序列的线性组合时,求解零状态响应的常用方法都是激励分解法,但最后结果形式复杂,难以化简和分析.本文提出一种直接求解及确定待定系数的方法.与激励分解法相比,该方法结果表示简单,计算方便,既可以计算零状态响应,也可以计算全响应.     

离散信号的近均值滤波

本文提出一种“近均值滤波”的非线性滤波的方法,并对其特性加以证明。这种方法在平滑噪声的同时,使信号的边缘得到保护。因此,在数字信号处理中,是一种有用的方法。     

离散时间模拟信号处理方式引人注目无需特殊的RF CMOS工艺

在“ISSCC 2004”上，数字技术并不特别抢眼。但是，却有格外吸引与会技术人员目光的成果发表，那就是美国TI公司的蓝牙技术接收集成电路（见图A I）。     

离散时间序列卷积和的求法

卷积是“信号与系统”课程中的重要概念。连续卷积与有限长序列的卷积和在文献中给出了多种解法。文中系统介绍了求解一般离散时间信号卷积和的几种方法,包括解析法、列表法、利用卷积和性质求解及应用单位样值信号求解,并通过举例加以说明。最后,对各种解法进行了比较和讨论。     

Stability determination of two-dimensional discrete-time systems

In determining root distribution of univariate polynomials with real or complex-valued coefficients, the Bistritz tabular form offers a significant computational advantage. Stability studies of two-dimensional (2-D) discrete-time systems involve univariate polynomials possessing parameter-dependent coefficients, where the parameter takes values on the unit circle in the complex plane. This paper investigates the application of Bistritz tabular form in determining stability of 2-D discrete-time systems, and for this purpose we present two algorithms. Both algorithms utilize a recent result that has established the relationship between Schur-Cohn minors and the entries of the Bistritz tabular form corresponding to a given polynomial. A comparison between the use of the modified Jury table and the Bistritz table in stability checking of 2-D discrete-time systems is also presented.     

A note on mathematical formulation of discrete-time linear systems

The goal of this paper is to point out and improve some inaccuracies in the mathematical formulation of linear discrete-time systems. We suggest an exact definition which covers all linear systems used in practice. We show that the proof of the fundamental theorem of stability from [1,2] is incomplete and we give a correct one.     

Robust pole placement in discrete-time systems

The problem of robust pole placement via a state-space feedback is discussed for discrete-time systems. It is assumed that a discrete-time system is described in terms of the state-space equation x(k+1)=Ax(k)+bu(k),y(k)=c^Tx(k)+eu(k) with uncertain entries of matrices (c, A, b,e). A feedback matrix f is calculated such that the real stability radius of the characteristic polynomial of the closed-loop system is possibly maximal.     

A canonical form for discrete-time systems defined overZ + *

It is shown that for each memberG of a large class of causal time invariant nonlinear input-output maps, with inputs and outputs defined on the nonnegative integers, there is a functionalA on the input set such that (Gs)(k) has the representationA(F _k s) for allk and each inputs, in whichF _k is a simple linear map that does not depend onG. More specifically, this holds—with anA that is unique in a certain important sense—for anyG that has approximately finite memory and meets a certain often-satisfied additional condition. Similar results are given for a corresponding continuous-time case in which inputs and outputs are defined on ₊. An example shows that the members of a large family of feedback systems have these A-map representations.     

An algorithm for stability determination of two-dimensional delta-operator formulated discrete-time systems

The recent interest in delta-operator (or, -operator) formulated discrete-time systems (or, -systems) is due mainly to (a) their superior finite wordlength characteristics as compared to their more conventional shift-operator (or,q-operator) counterparts (or,q-systems), and (b) the possibility of a more unified treatment of both continuous- and discrete-time systems. With such advantages, design, analysis, and implementation of two-dimensional (2-D) discrete-time systems using the -operator is indeed warranted. Towards this end, the work in this paper addresses the development of an easily implementabledirect algorithm for stability checking of 2-D -system transfer function models.Indirect methods that utilize transformation techniques are not pursued since they can be numerically unreliable. In developing such an algorithm, a tabular form for stability checking of -system characteristic polynomials with complex-valued coefficients and certain quantities that may be regarded as their corresponding Schur-Cohn minors are also proposed.     

信号与系统与数字信号处理两课程教学内容的一种整合方案

从培养面向21世纪高等工程教育培养人才应具有素质考虑,参照高等学校工科电课程教学指委会1998年提出的“电工电子系列课程和教学内容的改革的几点建议”精神,就“信号与系统”与“数字信号处理”两课程的教学内容,提出一种整合方案。     

一种智能广播监测器的研究与实现

针对广播信息安全监测的迫切要求以及目前广播过程中不能及时、有效处理突发情况等缺点，结合嵌入式系统、音频数字处理和信号处理等技术，设计出一款具有较高实用价值与技术水平的智能广播监测器，不但满足了广播安全监测的要求，同时保证了广播的连续性，提高了广播质量。     

ADSP—2106X在高速并行信号处理系统中的应用

ＡＤＳＰ－２１０６Ｘ是当前性能最高的浮点ＤＳＰ处理器这一,利用它可方便地构成多处理器并行数据信号处理器,统一的地址空间允许处理器间直接存取每片ＡＤＳＰ－２１０６Ｘ的片内ＳＲＡＭ,片内分布总线总裁逻辑允许直接把六片ＡＤＳＰ－２１０６Ｘ和一个主机组成一个多机并行系统。本文讨论了基于ＡＤＳＰ－２１０６Ｘ的数字信号处理器的设计方法并给出了它在“移位付立叶变换”算法中的应用。     

数字信号处理及其通信系统设计

本文通过对数字信号处理器、外围支持系统、信号输入输出及其数字通信系统的综合分析讨论，总结了高速数字信号处理及其通信系统的一般设计原则和技巧，并以此设计了一个多速率的实时语音编解码及其通信系统，得到了良好的实际应用效果。     

Stability of discrete-time systems joined with a saturation operator on the state-space: Yet another version of Liu-Michel's criterion

A novel criterion for the global asymptotic stability of fixed-point state-space digital filters using saturation arithmetic is presented. The criterion, which is basically a new version of an earlier criterion due to Liu and Michel, is a generalization and improvement over a recently reported criterion. The generalization is due to the fact that the use of even unsymmetric Lyapunov matrix P is permitted. An example illustrating the improvement realized from the present criterion is given.