MC12013—MC145152频率合成器

本文叙述了利用芯片MC145152构成低功耗、小体积频率合成器的整机原理和设计方法。     

MATLAB图像工具箱的应用

本文主要讲述MATLAB图像工具箱运用实例：通过图像分割、调整、锐化等处理,对目标图像的进行清晰化处理。MATLAB 中的工具箱也有许多函数的灵活运用于图像处理技术,其工具箱具有很强的可靠性和开放性,同时可以把自己的经验代码加到工具箱中,改进各种函数功能,实现自己需要的各种功能。在图像技术处理中使用MATLAB 语言可以迅速实现图像处理,能较大提高图像处理效率,为现实应用提供了持续改进条件。     

频率合成器的应用方向及前景

频率合成器是利用一个或多个标准信号,通过各种技术途径产生大量离散频率信号的设备,分为直接合成和锁相环合成两种。随着科学技术的发展,频率合成器应用越发广泛,其中单环锁相环频率合成器,直接数字合成（DDS）激励锁相环（PLL）的方式越来越受到关注,本文针对频率合成器在各个方面的应用及广泛的应用前景进行了深入研究。     

MATLAB DAQ工具箱的开发和应用

在球磨机负荷控制系统数学模型建立过程中，我们采用MATLAB进行信号的获取和分析。本文介绍了MATLAB DAQ（Data Acquistiton的缩写）工具箱及其在球磨机负荷控制系统数学模型建立中的具体应用。     

基于MATLAB优化工具箱的键的优化设计

建立键最小体积的数学模型,利用MATLAB软件的优化工具函数,实现键的尺寸优化设计,使得在强度满足的情况下,键宽b和键高h的取值小于标准值,减少了由于键的存在对轴、毂的削弱.     

E4408B频谱分析仪频率合成器的故障检修

总结了E4408B频谱分析仪频率合成器的工作原理,提出了相应的故障诊断方法;以典型的故障检修实例介绍其元件级维修的具体方法.     

基于FPGA的数字频率合成器(DDS)

基于DDS的基本原理和正弦函数的对称性,通过FPGA芯片RAM结构设计一个DDS系统,通过它可以得到频率可以任意改变的正弦模拟信号。     

基于MATLAB优化工具箱的柴油发电机组的优化运行

借助MATLAB中的优化工具箱,对多台不同容量的柴油发电机的并联运行进行优化.根据等微增率原理,对柴油机组的总耗量建立了目标函数.为了使柴油机经济稳定可靠运行,在总负荷一定的条件下通过柴油发电机组对负荷供电,在符合各个柴油发电机运行上、下限的情况下,使每台柴油发电机都运行在比较理想的工作点,减少了能源消耗.     

多带超宽带OFDM系统射频频率合成器的研制

针对通信系统中使用的传统锁相式频率合成器难同步的缺点,提出了采用直接数字频率合成器(DDS)和锁相环(PLL)技术设计应用于多带.正交频分复用超宽带(MB-OFDM UWB)系统的射频频率合成器方案,并研制了用于试验的合成器.该方案可有效解决系统射频电路的同步问题,提高频率分辨率,降低相位噪声,改善载波频偏对 OFDM 系统影响,提高系统性能,同时还可以降低基带算法的复杂度.仿真与测试结果表明,该频率合成器指标满足 MB-OFDM UWB 系统要求,可应用于实用系统中.     

数字PPL频率合成器的原理与使用

中波广播发射机载波频率振荡器能在531KHZ-1602KH频段内提供,1KHZ为间隔的107l@I~,,率点。这些频点的载波振荡频率稳定度和精度都应满足系统的性能要求,并能迅速变换。显然常用的晶体振荡器无法满足上述要求,因为尽管晶体振荡器能提供高稳定的振荡频率,但其频率值单一,只能在很小的频率段内进行微调。频率合成技术则是能够实现上述要求的一种新技术,数字PLLN率合成器是目前应用最广泛的一种频率合成器,它与模拟PLb~,率合成器的区别在于数字PLL中采用除法器（分频器）,而不是用频率减法器来降低输入鉴相器频率的。由于分频器可以很方便的用数字电路来实现,而且还具有可储存可变换的功能。因此它比一般的模拟PLL频率合成器更方便、更灵活。此外,数字电路易于集成和超小型化。     

条件接收系统中机顶盒和智能卡安全通信协议

提出了条件接收系统中智能卡和机顶盒安全通信的协议.协议使用了Schnorr身份方案实现机顶盒对智能卡的认证,并使用一个非对称密码系统实现智能卡对机顶盒的认证.协议最小化了智能卡的在线计算负担,同时保持与其它协议同样的安全水平.对协议的安全性和性能进行了分析.分析结果表明,协议对于恶意攻击是鲁棒的,并且非常适合于只有有限处理能力的智能卡.而且,协议为不同的条件接收系统使用同样的机顶盒提供了可能,因为在协议中机顶盒不需要事先存储任何条件接收系统的秘密私有数据.     

无线通信测试仿真系统的设计与实现

为满足高校实训教学实际需要,设计开发综测仪仿真教学系统软件.该仿真系统采用C#语言开发设计,在技术实现方面,采用面向对象仿真方法、GDI+绘图和蒙特卡罗等方法对仿真中的复杂设计进行处理,实现综测仪的模拟测试仿真过程,达到仿真测试结果与真实仪表环境下的测试效果相一致.在仿真教学方面,该系统结合高校教学实际情况提供多种实用性的教学管理功能.结果表明:综测仪仿真教学系统具有很强的实用性,可作为高校无线测量的仿真教学软件进行应用教学.     

基于MATLAB的卷筒纸印刷机张力控制系统的建模与仿真

为了精确研究滚筒印刷的张力特性及控制策略,建立了一个较精确的开卷张力动力学模型,利用MAT-LAB强大的建模、仿真功能,开发了一个开卷张力仿真模型,采用PID对其进行控制,由此构建了完整的卷筒纸印刷机开卷张力控制仿真系统。对多个张力扰动因素进行了研究与仿真,并给出了不同扰动占主导时的张力控制系统仿真结果。     

防振缓冲理论在纸箱包装系统设计中的应用

提出了防振缓冲纸箱包装系统的力学模型并分析了其规律和特性；介绍了防振理论在纸箱包装系统设计中的应用，为提高纸箱包装系统防振缓冲能力，减少包装破损损人提出了合理的设计方法和途径。     

Analysis of structures subjected to random wind loading by simulation in the frequency domain

The closely related methods of transfer matrices and direct numerical integration have been extensively used in the analysis of free standing structures. In case of structures subjected to dynamic loading, the method is particularly suitable to analysis in the frequency domain, enabling the consideration of arbitrary linear time-dependent material behaviour without additional difficulties. In this paper, a method is proposed to simulate stationary random processes in the frequency domain and it is applied for analysis of structures under along-wind action. The method requires less computational effort than standard procedures to obtain the power spectral density function of response quantities of interest and, since the solutions are obtained by simulation, may be extended to include in the formulation some types of non-linearity. Furthermore, it can be advantageously employed in the dynamic analysis of thin-walled open section beams, for which other alternatives are rarely available. The method proposed is applied to various free-standing towers and chimneys, for which response measurements are available, allowing a direct comparison of theoretical and experimental results.     

A simulation based approach to analyse the effects of job release on the performance of a multi-stage job-shop with processing flexibility

Workload control concepts are advocated as one of the new production planning and control methods. In its elaborated form, workload control includes three major decision levels: job entry, job release and priority dispatching. In each decision level, several decision points which have significant impact on the effectiveness of the production planning and control are defined (i.e., acceptance/rejection, due date assignment, etc.). Workload control systems should consider all of these decision points simultaneously in order to improve the effectiveness of production planning and control. In addition to these decision levels, flexibility of the shop can also be included as the fourth decision level which allows the shop capacity to be adjusted as new orders enter the system and as they are released to the shop floor. In this study, simulation models which enable the effect of each decision level within a workload control concept to be explored are developed and tested. The results reveal that simultaneous consideration of decision levels is critical and can improve the effectiveness of production planning and control.     

A Novel Approach to the Convergence Proof of Ant Colony Algorithm and Its MATLAB GUI-Based Realization

1 IntroductionAnt colony algorithm was inspired by the observation of real ant colonies[1]. The inspiring source ofant colony algorithm is the foraging behavior of real ants which enables them to find shortest pathsbetween nest and food sources. The promising ant colony algorithm is a relatively new optimizationtechnique, which is also a model-based approach for solving hard combinatorial optimization prob-lems[2]. Although ant colony algorithm for the heuristic solution of combinational optim…     

基于MATLAB技术的LPG储罐重大事故动态模拟评价系统开发与应用

为提高人们对LPG储罐重大事故预测、预防水平和抗灾害能力,根据LPG储罐泄漏、扩散、着火、爆炸等事故的发生和发展,建立一套LPG储罐重大事故动态模拟评价方法,在此基础上进行软件系统的功能、模块和数据设计,应用VC与MATLAB可视化面向对象接口技术实现事故后果模拟评价及特征参数随时间、距离变化过程的可视化。该软件能够脱离MATLAB环境运行,实现了评价结果通过图形直观动态显示,可预测特定位置的破坏情况,评价事故影响范围和危害程度。工程应用表明,该评价系统软件用于LPG储罐重大事故的安全评价是可行的,并可用于其他具有着火和爆炸危险性、毒性的重气或液化气体的生产和贮存企业的安全评价。     

Polysilicon high frequency devices for large area electronics: Characterization, simulation and modeling

Laser Crystallised Polysilicon Thin Film Transistors have now sufficient good conduction properties to be used in high-frequency applications. In this work, we report the results for 5 μm long polysilicon TFTs obtained at frequencies up to several hundred MHz for applications such as RFID tags or System-On-Panel. In order to investigate the device operation, DC and AC two-dimensional simulations of these devices in the Effective Medium framework have been performed. In the light of simulation results, the effects of carrier trapping and carrier transit on the device capacitances as a function of dimensions are analysed and compared. An equivalent small-signal circuit which accounts for the behaviour of these transistors in all regions of operation is proposed and a model for the most relevant elements of this circuit is presented. To validate our simulation results, scattering-parameters (S-parameters) measurements are performed for several structures such as multi-finger, serpentine and linear architectures and the most meaningful parameters will be given. Cut-off frequencies as high as 300 MHz and maximum oscillation frequencies of about 600 MHz have been extracted.     

A methodology for evaluation of metal forming system design and performance via CAE simulation

In the current metal forming product development paradigm, product cost, time-to-market and product quality are three overriding issues, which determine the competitiveness of the developed products. In the up front design process, the first 20% of design activities commits to about 80% of product development cost and product quality issues. How to conduct ‘right the first time’ design is critical to ensure low development cost, high product quality and short time-to-market. To address these issues, state of the art technologies are needed. Traditionally, computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies provide solutions for representation of design intent and realization of design solution physically. However, it is difficult to address some critical issues in the design of forming process, tooling structure, material selection and properties configuration, and finally the product quality control and assurance. Computer-aided engineering (CAE) technology fills this gap as it helps practitioners generate, verify, validate and optimize design solutions before they are practically implemented and physically realized. In this paper, a methodology for evaluation of metal forming system design and performance via CAE simulation is developed. The concept of metal forming system and its design is first articulated and how the CAE technology helps design and design solution evaluation is then presented. To assess and evaluate the performance of metal forming systems, quantitative design evaluation criteria are developed. Through industrial case study, how the developed methodology helps metal forming system design and evaluation is illustrated and its efficiency and validity is finally verified.