一种简易的智能数字芯片检测装置

针对实验教学过程中数字芯片型号识别和内部故障等问题,设计了一种基于MSP430系列单片机的低功耗智能数字芯片检测装置。利用布尔函数关系式建立了故障集,并对测试芯片生成测试向量,通过单片机编写待测芯片逻辑功能的测试程序,用单片机I/O对待测芯片的逻辑功能进行检测,并将检测结果与存储的芯片逻辑功能进行对比,判断待测芯片是否存在故障。实验结果表明,该装置能够实现对双列直插式数字芯片的快速检测,并显示数字芯片型号或故障,具有体积小、检测速度快,使用方便等优点。     

基于标准DDR总线的内存扩展芯片的设计与实现

随着计算机领域进入大数据时代,数据的快速增长和以数据为中心的发展趋势给现有的计算机存储带来了机遇和挑战。传统的标准双倍速率(DDR)总线接口采用固定的时序,难以加入各种扩展功能,若引入新型内存器件,则存在时序兼容问题。为此基于现有的DDR协议,本文设计实现了内存缓冲扩展芯片。该芯片与处理器端的物理连接采用标准DDR总线,消除了兼容性问题;并且在芯片逻辑设计中,增加对可变延迟访问和扩展访存指令的支持,为内存增加了智能性,可用于内存加速和内存扩展。本文详细介绍了该芯片采用的关键技术,经过中芯国际40 nm工艺流片验证,该芯片逻辑功能正确,运行稳定。在DDR3-1066频率下,该芯片可满足标准DDR3内存读写时序,并在龙芯3A系列主板上顺利启动Linux内核。芯片性能评估结果表明,应用扩展的访存指令可实现访存加速。     

VLSI超大规模集成电路测试和验证的发展趋势

随着深亚微米级材料的应用，VLSI器件进一步推动了半导体技术领域的发展，传统的测试和验证方法已不能满足需要且成本较高，基于Core的系统级芯片要求芯片设计者必须改变以往的开发方式，以便缩短上市时间，扩大销售额。一种嵌入式的测试方法应运而生，它能使芯片设计者在较短的时间内生产出高质量的产品，提高利润、增加市场知名度，且大大减少了系统验证、检测和调试的时间。本文着重讨论嵌入测试技术，分析该技术对产品的上市时间、产品质量以及生产成本所带来的影响。     

隧道协议的测试研究和实践

详细论述了隧道协议的一致性和互操作性测试的研究与实践。基于协议的测试需求分析，选择并实现了穿越测试法作为隧道协议的一致性测试方法。在实践过程中通过增加测试描述和扩充参考实现的功能，不仅实现了测试过程中对被测系统的自动配置，而且增强了测试例的可读性。对于隧道协议的互操作性测试，尝试提出一种基于并发TTCN操作语义的互操作性测试框架。     

CAT技术应用于变压器例行试验的探讨

介绍了计算机辅助测试（CAT）技术在电工电气试验中的应用。以电力变压器例行试验为例，阐述了一套微机型变压器CAT自动测试系统实现变压器七个例行试验项目基本试验功能的方法，具体探讨了该测试系统在试验数据采集、A／D转换等方面的软、硬件实现过程及CAT技术中的数据管理及测试诊断问题；基于误差理论对试验数据进行误差分析，简要的给出了采用滤波电路对测试误差进行抑制的结果；说明了采用CAT测试系统进行变压器例行试验的可行性、科学性和必然性。     

晶体管模型参数的计算机辅助测试

本文介绍了一种基于VXIbus模块仪器的晶体管模型参数自动测试方法,并形成了一个实用的计算机辅助测试系统。各参数根据其在GP模型中的物理意义,测得特定工作状态下的电流、电压值,经计算处理而得到。与传统测试方法相比,该测试方案简单实用,减少了众多复杂的测量仪器,具有使用方便、自动化程度高等优点。可应用于电子线路的计算机辅助分析,尤其可用于电路的故障诊断。在模拟印制板故障诊断系统中的实际应用表明,此方法能提供电路故障诊断系统可以接受的计算精度。     

基于AD9850的频率特性测试仪

详细介绍基于DDS技术的网络频率特性测试仪的原理、组成及其功能,包括产生扫频信号的芯片AD9850和七阶椭圆滤波器、基于AD8302的被测网络增益相位检测电路、基于施密特触发器和D触发器的相位极性判断电路,该仪器主要应用于对宽带放大器,滤波器以及其它有源或无源线性网络频率特性的测试。用液晶显示器显示幅频特性,相频特性以及单点测试曲线。     

40Gbps甚短距离并行光传输系统接收电路的设计与实现

给出了符合OIF-VSR5规范的40Gbps甚短距离光传输系统接收电路的设计与实现。该接收电路实现简单,由一片转换芯片及光接收模块构成。其特点是充分利用现场可编程门阵列(FPGA)内嵌的高速收发器成功实现了16×2.488Gbps和12×3.318Gbps信号的发送和接收,并且在一片FPGA上实现了诸如时钟数据恢复、串/并转换、帧同步、通道对齐、12-16路映射等全部功能。基于二分查找法的帧同步电路则大大提高了转换芯片的工作速度。Signaltap Ⅱ逻辑分析仪的测试结果表明接收电路工作正常,性能良好。在此基础上,给出了VSR5实验系统的点到点测试方法,通过12通道垂直腔面发射激光器并行接收模块和7m 12芯多模带状光纤,将发送电路与接收电路相连,实现了OC768/STM-256 40Gbps的点到点测试,测试结果表明系统误码率小于10~(-12)。     

系统芯片 IDDQ 可测试设计规则和方法

目的：为了使IDDQ测试方法对SOC（系统芯片）IC能继续适用，必须实现SOCIDDQ的可测试性设计，解决因SOC设计的规模增大引起漏电升高的问题。方法：传统的电路分块测试方法存在需要增加引腿代价，因此是不实际的，本文提出了一种通过JTAG边界扫找控制各个内核电源的SOCIDDQ可测试设计方法。结论：实验表明该设计不要求专门的控制引腿，硬件代价是可忽略的，结论：本文提出的方法可有效地用于系统芯片的IDDQ测试。     

基于555芯片的单稳态电路设计

555定时器集成芯片是一种集数模等多功能为一体的中规模集成功能电路,其具有电路结构简单、使用灵活方便等优点,被广泛应用到脉冲产生、整形、以及定时和延迟等自动控制电路中。本文在介绍了基于555定时器电路的单稳态触发器电路的逻辑组成和工作原理后,详细分析了基于555定时器集成芯片的照明触摸开关电路的实际设计技术要点和设计流程步骤。     

Laser desorption ionization-time-of-flight mass analysis of perfluoropolyether monolayer directly from hard disk medium surface

Modern life is dependent on computer technology, and because the volume of digital data in the world is increasing rapidly, the importance of data storage devices is also increasing rapidly. Among them, demands for magnetic disk drive well-known as hard disk drives is quite huge and information recording density on the disk media is continuing to grow dramatically. For the research and development of the magnetic disk media, it is critical to investigate and characterize the lubricant layer formed on the disk media surface. However, it is difficult because the layer is only a monolayer which has only approximately 1 nm thickness in many cases. Although matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) measurements of monolayers have already been reported (Su, J.; Mrksich, M. Langmuir, 2003, 19, 4867-4870), lubricants used here are (co)polymers which have molecular weight distributions and are mixtures of various degrees of polymerization. This can reduce the sensitivity of MS measurement because the number (or density) of distinct single molecular species is lower than for homogeneous samples. In this report, direct measurement and characterization of lubricant monolayers using the LDI-TOF-MS instrument is performed to gain insight into detailed information like average molecular weight, polymer distribution, and two-dimensional mapping directly from magnetic disk monolayers. To our knowledge, this is the first time such information was acquired directly from hard disk media. The technique reported here might open up new possibilities also for investigations of various electronic devices other than magnetic hard disks.     

USE OF THIN SOLID FILMS AT HEAD/MAGNETIC MEDIA INTERFACES

The lubrication of head / disk interlaces in magnetic hard disk drives by physically processed thin films was investigated. Sputtered gold films showed no useful endurance as a protective / lubricating film. Ion-plated carbon films and hydrogenerated carbon films (i-carbon) were effective for preventing tribological damages in magnetic recording media, while amorphous carbon films (a-carbon) were ineffective. The longest durability was found for i-carbons. Raman scattering showed that i-carbons contained much sp³ component, and microindentation test signified that i-carbon films were twice as hard as amorphous carbon films. As a protective film, i-carbon seems very promising, but hard materials should be selected as heads to avoid quick wear of the head. Sufficient performance of i-carbon films may lead to application of thin solid lubricants to hard disk drives.     

Single flux quantum signal transmission techniques in building practical RSFQ circuits

The practical implementation of rapid single flux quantum (RSFQ) technology requires much more complexity than the presently developed circuits. Multiple chips have to be integrated with a technology that is reliable at cryogenic temperatures. The interchip and intrachip data transmission speed of tens of GHz has to be supported. Also, the large RSFQ circuits need serial biasing to reduce the amount of the bias current. The test circuits were designed, simulated, fabricated with Nb technology, and tested at a temperature of 4.2 K. Test results at GHz frequencies showed that SFQ pulses can be successfully transmitted over an extensive distance in a chip, between chips, and over the circuits in different ground planes.     

STARS: Knowledge based tools for safety and reliability analysis

The paper discusses the issues involved with computer support for systems reliability modelling. The problems related to computer aided logic model construction are explained. Expert system technology offers promising perspectives to solve these problems. Combined with graphics interface and analysis capabilities, a tool based on expert system technology can provide a natural engineering oriented environment for computer assisted reliability and safety modelling and analysis. Expert systems can explain their reasoning so that the analyst can become aware of how and why results are being obtained. Hence, the learning aspect involved in manual reliability and safety analysis can be maintained and improved.

Next the STARS project is presented. STARS (Software Tool for the Analysis of Reliability and Safety) aims at developing an integrated set of Computer Aided Reliability Analysis tools for the various tasks involved in systems safety and reliability analysis including hazard identification, qualitative analysis, logic model construction and evaluation. For fault tree construction, a frame/rule based expert system is used, in which the deductive (goal driven) reasoning and the heuristics, applied during manual fault tree construction, is modelled.     

Synchronous servo scheme using maximum-likelihood detectors

For magnetic disk drives, we have developed a scheme for synchronous servo with maximum-likelihood (SSML) detection that is synchronous around the entire circumference of the track and utilizes ML estimation to detect head position, clock mark phase, and track addresses. Compared to the conventional asynchronous sector servo scheme, the SSML scheme has many, much shorter, servo areas-typically several hundred-distributed on the disk. This results in higher servo information rate, which will be needed for future high-track-density disk drives with a wide servo bandwidth. We analyze the performance of the SSML scheme, including the format efficiency. We discuss a limitation of the synchronous servo scheme with respect to the number of servo areas, and we show an appropriate region for its application. Feasibility of the SSML scheme has been demonstrated in prototype 2.5-in hard disk drives.     

Data storage in 2000-trends in data storage technologies

Recent projections by experts in computer systems and semiconductor technology indicate that in the year 2000, personal computers will have a processing speed of 100 million instructions per second and a semiconductor RAM capacity of 1 Gbyte. To work with such a system, data storage devices will need to provide more than 10 Gbytes of capacity and a data rate of 100 Mbyte/s. The advances required by magnetic and magnetooptical disk drives to meet these requirements are examined. Plausible system configurations for achieving these goals are described. A magnetic disk drive utilizing eight 3.5-in. disks on one spindle appears to be a possible configuration. Because of a larger areal density, a magnetooptical disk drive could meet the capacity requirements with only a single 3.5-in. disk. On the other hand, achieving the 100-Mbyte/s data rate and access times comparable to those of magnetic disk systems will require some technological breakthroughs. Without these breakthroughs and assuming magnetic disk progress as expected, magnetooptical disks are expected to provide many of the functions which floppy disks provide today-transfer of programs and databases between systems and economical offline storage     

Effects of magnetic fields on flexible disk drive performance

The read/write heads in flexible disk drives operate in the presence of AC and DC magnetic fields generated by solenoids, motors, recording head erase structures, circuit board components, and external sources such as CRT flyback transformers present in "smart terminals and word processors. Time varying magnetic fields induce signal on the read/write coil and introduce interference. This interfering signal increases the error rate and can cause "extra bits". Steady state fields cause shifts in the location of transitions, which also translates into higher error rates. The benefits derived from various shield configurations in and external to the flexible disk drive are presented.     

Magnetic domain-wall dynamics in a submicrometre ferromagnetic structure

As fabrication technology pushes the dimensions of ferromagnetic structures into the nanoscale, understanding the magnetization processes of these structures is of fundamental interest, and key to future applications in hard disk drives, magnetic random access memory and other 'spintronic' devices. Measurements on elongated magnetic nanostructures highlighted the importance of nucleation and propagation of a magnetic boundary, or domain wall, between opposing magnetic domains in the magnetization reversal process. Domain-wall propagation in confined structures is of basic interest and critical to the performance of a recently demonstrated magnetic logic scheme for spintronics. A previous study of a 500-nm-wide NiFe structure obtained very low domain-wall mobility in a three-layer device. Here we report room-temperature measurements of the propagation velocity of a domain wall in a single-layer planar Ni80Fe20 ferromagnetic nanowire 200 nm wide. The wall velocities are extremely high and, importantly, the intrinsic wall mobility is close to that in continuous films, indicating that lateral confinement does not significantly affect the gyromagnetic spin damping parameter to the extreme extent previously suggested. Consequently the prospects for high-speed domain-wall motion in future nanoscale spintronic devices are excellent.     

磁性载体记录的稳定性探索

本文总结了有关贮存在各种磁性记录载体中信息的保存性的一些基本科学技术知识，包括：录音带，录像带，计算机磁带，软磁盘，硬磁盘，光磁盘等，全文分两期登出，本期登其第一部分，内容主要为：磁性记录材料的特性和稳定性，磁性粒子，下期内容为：粘合剂，聚酯带基，环境因素影响等。     

Design of synthetic biological logic circuits based on evolutionary algorithm

The construction of an artificial biological logic circuit using systematic strategy is recognised as one of the most important topics for the development of synthetic biology. In this study, a real‐structured genetic algorithm (RSGA), which combines general advantages of the traditional real genetic algorithm with those of the structured genetic algorithm, is proposed to deal with the biological logic circuit design problem. A general model with the cis ‐regulatory input function and appropriate promoter activity functions is proposed to synthesise a wide variety of fundamental logic gates such as NOT, Buffer, AND, OR, NAND, NOR and XOR. The results obtained can be extended to synthesise advanced combinational and sequential logic circuits by topologically distinct connections. The resulting optimal design of these logic gates and circuits are established via the RSGA. The in silico computer‐based modelling technology has been verified showing its great advantages in the purpose.Inspec keywords: biocomputing, biological techniques, combinational circuits, genetic algorithms, logic design, logic gates, sequential circuitsOther keywords: in silico computer‐based modelling, RSGA, sequential logic circuits, XOR gates, NOR gates, NAND gates, OR gates, AND gates, Buffer gates, NOT gates, fundamental logic gates, cis‐regulatory input function, real‐structured genetic algorithm, artiflcial biological logic circuit design