An overview of radiation effects on electronics in the space telecommunications environment

Trapped protons and electrons in the Earth’s radiation belts and cosmic rays present significant challenges for electronics that must operate reliably in the natural space environment. Single event effects (SEE) can lead to sudden device or system failure, and total dose effects can reduce the lifetime of a space-based telecommunications system. One of the greatest sources of uncertainty in developing radiation requirements for a space system is accounting for the small but finite probability that the system will be exposed to a massive solar particle event. Once specifications are decided, standard laboratory tests are available to predict the total dose response of MOS and bipolar components in space, but SEE testing of components can be more challenging. Prospects are discussed for device modeling, and for the use of commercial electronics in space. In addition, technology trends are discussed for the radiation response of microelectronics in space.     

A Computerized Test System for Communications Equipment Subassemblies

This paper describes an automatic test system for factory testing of telephone carrier equipment channel units. The system is intended for high volume subassemblies such as those found in pulse-code-modulation carrier systems where, typically, there are 24 units in each terminal. With the greater availability of minicomputers and digitally programmable instruments, a system is feasible at moderate cost. The system described uses a low-cost self-contained eight-bit minicomputer as the test sequence controller. Control information is transmitted to and from the various instruments by way of a data input-output buffer. A reed contact switching matrix is used to interconnect commercial equipment that is used to generate inputs and measure results. The resulting system is capable of making up to 100 functional tests on a channel unit in less than one minute. Significant savings have been possible in testing time and labor cost. Also, equipment reliability is improved because of uniform testing methods.     

低功耗冲击波超压测试系统设计

针对爆炸场测试现场的恶劣环境,为了提高测试系统的可靠性,提出了一种基于CPLD与AT8515单片机的低功耗冲击波超压测试系统,结合测试过程中压力信号的采集、存储这一问题,详细的阐述了压力测试系统的总体设计方案、工作原理及系统组成。试验表明：该测试系统具有抗干扰、抗高冲击、高可靠性、微功耗等优点,适用于恶劣环境下数据的存储测试。     

The intelligent building telecommunications infrastructure

The telecommunications infrastructure required for an intelligent building to support the overall telecommunications utility is considered, focusing on the wiring system. Emerging national standards that embrace all components of the telecommunications infrastructure are described. Basic infrastructure concepts are explained, and component details are examined. Important links between the infrastructure components and the emerging national standards are shown     

Software reliability estimations for telecommunications products

Reliability of software used in telecommunications networks is a crucial determinant of network performance. Software reliability (SR) estimation is an important element of a network product's reliability management. In particular, SR estimation can guide the product's system testing process and releasability decisions. SR estimation is performed using an appropriate SR estimation model. However, the art of SR estimation is still evolving. There are many available SR estimation models to select from, with different models being appropriate for different applications. Although there is no “ultimate” and “universal” SR model on the horizon (and there may not be one in the foreseeable future), methods have been developed for selecting a trustworthy SR model for each application. The present authors have been analyzing and adapting these methods for applicability to network software. Their results indicate that there already exist methods for SR model selection which are practical to use for telecommunications software. If utilized, these methods can promote significant improvements in SR management. The paper presents the results to date     

IPv6隧道代理设计实现中的关键问题研究

隧道技术应用于IPv4向IPv6过渡时期.手动隧道在大规模网络中难以配置和管理,采用隧道代理技术可以实现隧道自动管理,使得网络提供商可以为用户提供早期的IPv6接入服务.兰州理工大学IPv6试验床在Linux平台下,利用PHP技术自主设计开发了隧道代理系统,并对RFC3053提供的隧道代理基本模型进行了改进和细化.本文对其进行了介绍并阐述了隧道代理系统设计实现中的关键问题.     

一种基于TTCN的TD-SCDMA终端RRM一致性测试结构设计

RRM一致性测试是3G终端测试的重要组成部分,它对终端的研发和认证具有重要意义.本文分析了TD-SCDMA终端RRM一致性测试项,提出了一种基于TTCN的RRM一致性测试系统实现框架,并介绍了其内部结构和各个部分功能.这个结构已经用于实际的TD-SCDMA终端RRM一致性测试设备的研发中.     

一种TDMA无线自组织网络模拟验证系统设计与实现

针对 TDMA 无线自组织网络终端的组网测试需求，本文提出一种模拟验证方法， 将终端软件进行整体移植，搭建模拟组网环境并进行集中时隙调度，在完整保留终端组网功能的情况下，实现大规模组网测试验证。基于此方法，设计并开发了模拟验证系统。相对于全实物和半实物验证，系统兼具高有效性和低成本的特点。经过项目实际应用，该系统能够对 TDMA 无线自组织网络终端的组网功能和性能进行有效的测试验证。     

Confidence Limits for System Reliability: A Sequential Method

A sequential method is given for obtaining confidence limits for system reliability when ``pass-fail' test data have been obtained on components. Costs of testing are examined and a rule is derived for determining the order in which to test the components so that the average cost of testing is minimized. The method is presented first for series systems, but in Section IV the extension to parallel systems is considered and in Section V the procedure is applied to a series-parallel configuration. Comparisons are given with fixed sample-size testing and it is shown that the sequential method is statistically efficient and that many of the difficulties encountered when using fixed sample sizes are eliminated by testing sequentially.     

Architecture and design of a portable protocol tester

The architecture and design of a new generation portable protocol tester that includes most of the capabilities of dedicated protocol test systems and all of the capabilities of commercial portable testers are discussed. The general tester environment and model of the system under test as viewed by the protocol tester are presented. A conceptual model of a protocol tester that captures its main functional requirements is proposed, and the basic performance requirement is presented. The design and structure of a protocol tester that provides the functional and performance capabilities described are outlined. The implementation utilizes custom VLSI multiprocessors and a special-purpose multiprocessing operating system to allow active and passive testing of more than one system simultaneously. The testing software on each processor is organized as a single process consisting of protocol and test entities with event occurrences being implemented as procedure calls aided by hardware subprocessors. All testing methodologies defined by the ISO, including the ferry method, can be implemented and standardized conformance test suites supported. Suggestions for future extensions to the design are offered     

A Novel Test Strategy for Fine Pitch Wafer-Level Packaged Devices

This paper describes an innovative test strategy comprising a compliant elastomer mesh for testing fine pitch wafer-level package (WLP) devices. The test probe, hardware, and sample preparation processes are detailed. The components of the test hardware socket such as the SMA connectors, coplanar transmission lines on the PCB, via, off-chip interconnect, and elastomer mesh probe have been modeled. A complete system-level model, with off-chip interconnects on the WLP device pads, has been developed. The measurement and model demonstrate that the prototype test socket performs at 5 GHz with an insertion loss of about 3 dB. WLP device with Bed-of-Nail interconnects are characterized. Functional test features of the system are also addressed.     

基于系统连续运行的功率管老炼筛选方法

提出了一种可以在试验台上进行无条件的筛选、或对已装机而又存在某种隐患的功率管进行老炼筛选的方法,并介绍了如何进行老炼筛选应力的确定和控制,以及试验的过程检测和故障处理。通过理论分析和试验证明,这种方法是切实可行的,能达到老炼筛选的预期目标。     

Operation of an optoelectronic crossbar switch containing a terabit-per-second free-space optical interconnect

The experimental operation of a terabit-per-second scale optoelectronic connection to a silicon very-large-scale-integrated circuit is described. A demonstrator system, in the form of an optoelectronic crossbar switch, has been constructed as a technology test bed. The assembly and testing of the components making up the system, including a flip-chipped InGaAs-GaAs optical interface chip, are reported. Using optical inputs to the electronic switching chip, single-channel routing of data through the system at the design rate of 250 Mb/s (without internal fan-out) was achieved. With 4000 optical inputs, this corresponds to a potential aggregate data input of a terabit per second into the single 14.6 /spl times/ 15.6 mm CMOS chip. In addition 50-Mb/s data rates were switched utilizing the full internal optical fan-out included in the system to complete the required connectivity. This simultaneous input of data across the chip corresponds to an aggregate data input of 0.2 Tb/s. The experimental system also utilized optical distribution of clock signals across the CMOS chip.     

航空机载软件全数字仿真测试系统的设计与实现

针对航空机载软件测试环境与开发环境冲突、测试环境可控性和通用性差、非干预性测试困难的问题,分析了全物理实装测试环境、半实物仿真测试环境的优缺点,研究了全数字仿真测试技术,设计并实现了一种航空机载软件全数字仿真测试系统。该系统由仿真核心平台、仿真工具组件、协同仿真组件和人机交互组件构成,提供了航空机载处理器、内存、外设等多种可重用库。提出了基于底层虚拟机的动态二进制翻译技术、协同仿真时间同步和数据通信机制等关键技术,实现了航空机载软件全数字高速闭环仿真运行。工程实践证明,该系统能达到降低硬件设备的依耐性、简化测试环境搭建的复杂度、提高测试效率约42%的目的。     

电话语音识别中基于统计模型的动态通道

与桌面环境相比,电话网络环境下的语音识别率仍然还比较低,为了推动电话语音识别在实际中的应用,提高其识别率成了当务之急．先前的研究表明,电话语音识别率明显下降通常是因为测试和训练环境的电话通道不同引起数据失配造成的,因此该文提出基于统计模型的动态通道补偿算法（SMDC)减少它们之间的差异,采用贝叶斯估计算法动态地跟踪电话通道的时变特性．实验结果表明,大词汇量连续语音识别的字误识率(CER)相对降低约27％,孤立词的词误识率(WER)相对降低约30％．同时,算法的结构时延和计算复杂度也比较小．平均时延约200ms．可以很好地嵌入到实际电话语音识别应用中．     

Specifications for integrated circuits in telecommunications equipment

The demand for reliable semiconductor components in telecommunications systems has stimulated the preparation of two specification schemes, one for bipolar digital integrated circuits of the widely used standard-scale type and the other for MOS custom components representing large-scale integration. While sharing many reliability requirements with other applications, the telecommunications field is distinguished by the need for a long service life, often of several decades. Both schemes accordingly involve accelerated tests, particularly those employing elevated ambient temperatures. Other requirements are also common, as for encapsulation, but the main approaches differ. For bipolar circuits, the traditional component sampling procedure is adopted, details being given of the basis and background of some of the more important clauses. The MOS specification is based on design and process control, of which only the latter is presently developed featuring the use of a specially designed test component. Many years must elapse before the impact of the specifications can be judged objectively, but an encouraging impression has been obtained from early experience of their application.     

Enabling network management using Java technologies

The increasing integration of telecommunications networks creates possibilities for interoperability among their respective management systems, using common management interfaces for CMIP, SNMP, CORBA, and Java RMI. Many Java technologies related to network management have been developed; therefore, it is desirable to create a development environment using Java technologies. We explore a TMN-based management platform model and the applicable Java technologies. We demonstrate that the management platform can support certain candidate management interfaces as service components in a distributed computing environment. Lastly, we show that using Java technologies to provide network management indicates the feasibility of this management platform     

The convergence of telecommunications and computing: what are theimplications today?

As has been widely recognized for some time, the computing and telecommunications technologies are converging. This has meant different things at different times. In this review paper, we describe the current stare of convergence, and speculate about what it may mean in coming years. In particular, we argue that as a result of the horizontal integration of all media (voice, audio, video, animation, data) in a common network and terminal infrastructure, telecommunications and networked-computing applications are no longer distinguishable. Considering that the old terminology is no longer meaningful, we attempt to codify networked applications in accordance with their functionality and immediacy. As application functionality is increasingly defined in software, with commensurate cost-effective programmable terminals and means for distribution of applications over the network itself, we argue that user-to-user applications will be greatly impacted, moving into the rapid-innovation regime that has characterized user-to-information-server applications in the recent past. Finally we identify a number of areas where different technical approaches and design philosophies have characterized telecommunications and computing, and discuss how these technical approaches are merging and identify areas of needed research. We do not address complementary forms of convergence at the application or industrial level, such as convergence of the information and content-provider industries, but rather restrict attention to the infrastructure and technology     

A Time‐Constrained Information Processing Model in Ubiquitous Environments

As pervasive computing is widely adopted and reliable networks are becoming more easily accessible, there is a rapidly growing need to develop a mechanism to analyze and evaluate the performance of ubiquitous environments. This paper presents an information processing model which characterizes a ubiquitous environment where a variety of pieces of information need to be exchanged among devices within a system. The proposed model not only provides analytical tools to evaluate the performance of devices, but also makes it possible to identify key factors in designing a ubiquitous environment. For illustrative purposes, a test bed is constructed and the performance of the system is assessed based on the proposed model.