微型打印机打印技术分析

目前关于微型打印机应用的文献主要关注打印机与单片机系统的连接方法以及打印驱动程序设计。文中以RD系列针式打印机为例,给出了打印机与C8051单片机的连接及驱动程序,介绍了汉字打印技术、各类打印格式设置方法以及图形打印技术,给出了打印程序实例。     

天基雷达系统概念分析

针对天基雷达系统,对比分析了SAR、GMTI、AMTI以及DTED等技术模式的特点,研究了各种不同技术模式条件下的处理算法、体制特点和应用场合.并探讨了不同任务需求情况下根据覆盖性能对天基雷达卫星星座布局的要求.分析结果表明,天基雷达星座具有多种可变模式,功能先进.同时,天基雷达星座只需要有限的卫星数目就能达到全球覆盖的目的,具有很好的目标监视能力.分析的结论对于研究国际先进的天基雷达系统有着重要的指导意义.     

功率RF LDMOS的关键参数研究

在功率RF LDMOS器件中，击穿电压、截止频率fT和导通电阻Ron是器件性能的关键参数，为提高这几个器件性能参数可采取的各种措施又往往是互相矛盾和相互制约的. 文中研究了几个关键参数之间的关系和优化方案，以及国际上在这方面所开展的研究和取得的进展，为进一步的研究和探索提供参考.     

红外光源在有害气体检测中的应用研究

研究了红外光源在有害气体检测中的地位和作用。介绍了三类 不同红外光源的结构原理,比较了它们相互之间的优缺点,并对其应用情况进行了综述。然后详细分析 了气体检测技术对红外光源性能的要求以及在光源选型时的注意事项。最后,根据有害气 体检测的发展需求,阐明了红外光源的发展趋势。     

CCITT standardization of network node interface of synchronousdigital hierarchy

The main concepts and interfacing and multiplexing techniques for an NNI (network node interface) as set forth in CCITT (International Consultive Committee for Telephone and Telegraph) Recommendations are described. The objectives and history of the NNI standardization are reviewed together with concepts, basic requirements, and features of the NNI. The nine-row-based frame structure and the virtual container (VC) concept, which are the main features of the NNI, are introduced. The multiplexing principle and method, the detailed frame structure and overhead, and mapping methods related to the NNI are described. Applications of the NNI in the synchronous network and international interworking are presented. The future application of asynchronous transfer mode (ATM) is discussed     

光电编码器检测技术的研究现状及发展趋势

阐述了光电编码器的工作原理,按照编码方式的不同将光电编码器分为两类,总结比较两类编码器的性能特点及各自的优缺点。针对编码器检测技术的研究现状,介绍了常见编码器检测方法及模型,以及国内外现有的光电编码器检测技术及装置,并对比、分析、统计各检测方法的特点、适用场合及不足之处。并概括总结了未来光电编码器检测技术高精度、高效、高适用性的发展趋势。     

Validity of Execution-Time Theory of Software Reliability

This paper investigates the validity of the execution-time theory of software reliability. The theory is outlined, along with appropriate background, definitions, assumptions, and mathematical relationships. Both the execution time and calendar time components are described. The important assumptions are discussed. Actual data are used to test the validity of most of the assumptions. Model and actual behavior are compared. The development projects and operational computation center software from which the data have been obtained are characterized to give the reader some basis for judging the breadth of applicability of the concepts.     

Design of radiation-emission measurements of an air-traffic surveillance radar

The current work presents the procedure of designing and carrying out measurements of radiation emission from an air-traffic surveillance radar. The system requirements are first given, and then the equipment used is described. The steps to determine the operating characteristics of the radar are specified in detail. The necessary methods for manual power measurements and calculations are next explained. Since the final measurement system was fully automated, its main features (topology, protocol of operation) are also given. Finally, some measurement results taken during the initial phase of system operation are presented and discussed.     

Use of laser trimming for the development of a project for accuracy-normalization of the resistance of resistors in hybrid integrated circuits

The possibilities for laser trimming are studied, the disadvantages of this method are revealed, and the ways of developing this approach on the basis of computer-aided design and modeling are proposed. The hierarchy analysis method and the fuzzy-set theory are used to evaluate the normalization projects.     

Analysis of limit energy characteristics of planar demultiplexers

The energy gain and number of channels of a planar demultiplexer operating in a modern wave-length-division-multiplexing fiber-optic communication line are analyzed. The study involves the Fourier analysis and overlap integrals for complex fields. Reversible and irreversible demultiplexers are considered. The optimal parameters of the devices are determined. These parameters ensure the maximum gain and number of channels. Advantages and disadvantages of the devices are discussed, and desirable values of their parameters are recommended.     

Testability of parity checkers

Checkers are used in digital circuits to detect both intermittent and stuck-at faults. The most common error detectors are parity checkers. Such circuits are themselves subject to failures. The use of parity trees is outlined, and techniques for testing them are surveyed. The effect of the checker's structure on its testability is discussed. Several fault models are considered: single stuck-at, multiple stuck-at, and bridging faults. The effectiveness of single stuck-at fault test sets in detecting multiple stuck-at and bridging faults is described. Upper bounds for the double fault coverage of the minimal single fault test are given for different tree structures. The testabilities of some selected checkers are examined to illustrate the concepts developed. A built-in self-test is proposed     

Analysis of Variance of Traffic Usage Data

Procedures are developed and illustrated by application to real usage data of analysis of variance techniques for measuring components of variance in the data due to trend and arbitrary random variability in usage of equipment in a group as a whole. The usage data are obtained by periodic scanning of the equipment group at fixed intervals. Procedures for fitting the Polya distribution to the data are presented. Fitted Polya distributions are used to estimate the effects of trend on blocking. The procedures are extended to measuring and estimating the effects on blocking of day-to-day traffic variation and are illustrated by application to real usage data. A procedure is presented for adjusting estimates of variance for autocorrelation due to the usage measurement procedure and call holding times. The adjustment procedure is based on incomplete research and is, therefore, tentative. The effects of using a variance-stabilizing transformation of the data are shown. Other areas of application of the theory and procedures are discussed.     

气体声表面波传感器的研究进展

主要从声表面波(SAW)结构和敏感膜的角度综述了SAW气体传感器的研究现状。重点分析了国外出现的换能器新型结构,对其优点进行了初步分析,并和传统的SAW气体传感器结构做了比较,指出这些新结构尽管存在一些缺点,目前还不能取代传统的通用式结构,但是在某些特殊场合具有传统结构所不具备的优点。在敏感膜方面,主要从新材料方面入手,分析了目前主要使用的敏感膜材料,并结合SAW气体传感器的发展趋势,总结出敏感膜的发展方向。同时,对SAW气体传感器的其他组成部分如衬底材料和信号处理电路也作了简单的回顾,最后结合国内外研究成果对SAW气体传感器的发展做了展望。     

微惯性开关设计技术综述

微惯性开关作为微惯性传感器中的一类特殊器件在设计方面因应用背景的差异存在多种技术方案。通过描述惯性开关的工作原理和分类,介绍了国内外微惯性开关的研究概况,针对线性低g值微惯性开关闭合接触力小,触点接触弹跳,硅基导电性较差等共性问题进行了分析和讨论,提出了引入静电力或磁力以增大接触力,采用柔性接触结构以实现平稳接触,采用硅金属化工艺以实现良好的导电性等解决办法,可供微惯性开关结构设计时参考。     

光栅对压缩器在刻线不平行时的色散研究

针对光栅对压缩器刻线平行性失调会对压缩器色散特性造成严重影响这一问题,对刻线不平行的光栅对压缩器的衍射特性进行了分析,推导出了脉冲光束通过光栅对的光程。数值计算了2阶、3阶和4阶色散量,以及与光栅对严格平行相比的色散差。计算了输出脉冲的垂直谱位移,并将其作为刻线夹角的函数进行了分析。结果表明,存在刻线失调时,低刻线密度的光栅具有更好的优越性。     

Optical parameters of InP-based waveguides

The quaternary alloys InGaAsP, matched in their lattice constant to InP, are considered in view of optical-waveguide applications. The parameters, most important in this connexion, are the refractive index n and the optical absorption coefficient α. Both are calculated starting from quantities relevant to the binary constituents of the system InGaAsP. The results are compared with the relatively few experiments reported in the literature. The calculations are applied to film and rectangular waveguides, showing that they are sufficiently low in loss for integrated-optics applications.     

多孔硅的微结构对其Raman谱的影响

用场发射扫描电子显微镜研究了用直流化学腐蚀和脉冲电化学腐蚀方法制备的多孔硅(PS)的微结构,观察并测试了孔洞的垂直度、深度以及洞宽(直径),对PS的纵向微结构进行了二次电子图像和背散电子图像的分析.使用高灵敏的共焦显微Raman系统研究了纵向的Raman谱,同时分析了微结构对纵向Raman效应的影响.     

Comparison of Performance of Digital Modulation Techniques in the Presence of Adjacent Channel Interference

The performance of four digital modulation techniques are compared to one another when each is received in the presence of adjacent channel interference. The interfering waveforms that each modulation format sees are identical to the modulation format under consideration. The four types of modulation are QPSK, 8-PSK, 16QASK, and QPR. Upper bounds to the probability of error are derived and used to evaluate the relative merits of the different schemes.     

串联叠加式固态脉冲调制器的设计

介绍了固态调制器电路常用的拓扑结构,讨论了开关直接串联与加法器叠加两种拓扑结构的特点。设计了基于IGBT的串联叠加式固态刚管脉冲调制器,调制器通过充电电源变压器实现电位隔离,采用6路调制单元串联叠加,并利用脉冲变压器升压至40 kV。重点讨论了该类型调制器研制中的关键技术,分析了脉冲变压器铁芯饱和现象并提出解决方法;讨论了吸收电路的计算选取,给出了有无吸收电路时,IGBT的C、E两端电压波形;分析并解决了脉冲波形过冲控制以及电磁干扰噪声抑制问题。     

Development of the Technology of Magnetron Sputtering Deposition of LiPON Films and Investigation of Their Characteristics

The results of developing the technology of magnetron sputtering deposition of a LiPON solid electrolyte and an experimental investigation of its characteristics are presented. The basic processing operations and parameters providing the formation of films of the proper morphology, structure, and elemental and phase composition are described. The data of the measurement of the physical parameters of the films by cyclic voltammetry and potentiometry are represented.