Maintaining telephone switching software requirements

We discuss how telephony software requirements should be structured to reduce maintenance costs. "Feature interaction" problems have become a serious obstacle to add more features to telephone switches. We show why existing public switched telephone networks are hard to modify. We then argue that a more modular, layered requirements architecture can help. Finally, we survey approaches for such an improved telephone switching architecture and discuss them.     

Photonic switching technology: component characteristics versusnetwork requirements

Components for switching in the optical domain offer substantially different characteristics than electronic switches. However, except in special cases these characteristics do not immediately map well onto the network requirements as currently perceived so that there remains great challenge in establishing a viable technology. A variety of photonic switching technologies are discussed in this context. They are: passive pathway switches with electrical control active-path optical switches with electrical control; optically controlled electronic logic; optically controlled optical logic; and wavelength routing technologies. Optimum component and technology choices are discussed     

Uniform switching system by families of switching sets

A new mathematical method in coding theory that is applicable to various practical problems in communication systems is introduced. The uniform switching system based on k-sets is defined, and its cardinalities, an index system, and error correctabilities are studied. The cardinalities of a uniform switching system based on general families of switching sets are discussed. The asymptotic cardinality is obtained for the Reed-Muller codes of general order     

Optical switching speed requirements for terabit/second packet overWDM networks

Optical dynamics requirement for packet-over-WDM networks is analyzed. Optimization among optical switching speed, global resource availability, and local queuing considerations is performed, yielding multiterabit/second throughput capability by employing submicrosecond switching technology     

电视会议系统的中频切换技术

１前言中国广播电视节目的远距离传送最初是使用模拟微波,然后发展到使用模拟卫星传送。目前随着数字微波、数字卫星和光纤技术的发展,不少省市的模拟微波设备改成了数字微波设备。但是,模拟微波具有投资少、见效快、建设周期短、技术成熟、性能稳定、抗自然灾害能力强和易于维护等特点,仍被广泛地用于地（市）至县及县至乡镇的有线电视微波联网。近期正规微波厂家生产的模拟微波设备,从质量指标到设备的稳定性、可靠性均比以前的产品有了很大的提高,所以,目前已建成的地（市）至县及县至乡镇的模拟微波网中,大部分的枢纽站、中继站…     

A scalable ATM switching system architecture

The architecture of an asynchronous transfer mode (ATM) switching system for prototype applications is presented. The general concept to upgrade the existing ISDN switch with an ATM module is introduced, and the building blocks of this ATM module are described in detail. Switching of ATM cells is performed in a single application-specific integrated circuit (ASIC). ASICs can be cascaded to form large switching modules. Peripheral modules interface the ATM switch to external transmission systems and perform all ATM-related functions, including means for redundancy of the switching network. The redundancy scheme tolerates single failures without affecting the user information. A switching network architecture is shown to be capable of fulfilling varying demands in terms of the number of ports for ATM switches and cross connects, concentrators, and multiplexers     

TD-SCDMA系统接力切换技术

第三代移动通信标准TD-SCDMA系统根据其特点，提出了一种新的切换技术——接力切换。本文阐述了接力切换技术的算法设计以及实现流程，仿真结果表明了接力切换能有效利用系统资源，适用于码资源受限制的TD—SCDMA系统。     

A broadband optoelectronic packet switching system

A novel architecture is presented for a optoelectronic hybrid packet-switching system (HYPASS) for the distribution of multiple-bit-rate broadband services. HYPASS is based on an input-buffered/output-controlled arbitration protocol. This packet switch uses novel multiwave-length optical networks to accomplish routing and transmission of the packets. This system is specifically adapted to utilize the strengths of both optical and electronic technologies     

Changing technology in switching system software

The evolution of software techniques within the context of stored program controlled telephone switching systems is discussed in this paper. The paper starts with the transition from assembler coding to high-level language coding and then goes on to identify the operating system aspects of a telephone switch. Modern operating system concepts are presented in terms of standard telephone switch functions. The paper continues by describing the need for and development of modularity on a "plug-in" basis and closes by a discussion of mechanisms for simplifying on-line growth of telephone switches in terms of both size and feature complement.     

称重系统要求和分析

称重是工业领域非常普遍的一个应用,尤其在中国市场存在很多称重设备的设计和制造商。来自终端用户的产品千差万别,本文将着重分析、讨论这类应用的系统要求,探讨系统模拟输入前端的设计,因为这部分电路的性能直接决定了整个产品的精度水平。     

Software-reliability evaluation of the TROPICO-R switching system

The analysis and evaluation of the software of the TROPICO-R switching system are described. Failure data were collected over 27 months, including validation phase, field trial phase, and operational life. During this period 461 failure reports have been recorded. Two models (exponential and S-shaped) have been applied to these failure data, and have been analyzed according to their repetitive and predictive capabilities. It is found that it is difficult for the models to reproduce the observed failure data when changes in trend do not follow the model assumptions. The Laplace trend test is a major tool for guiding the partitioning of failure data according to the assumptions of model reliability growth. Only the S-shaped model has been considered for the analysis according to trend periods. Prediction yields good results over a time period of a few months, showing that reliability modeling is a major tool for test/maintenance planning and follow-up     

A coherent photonic wavelength-division switching system forbroad-band networks

A coherent photonic wavelength-division (WD) switching system, utilizing a coherent wavelength switch (λ switch), is proposed. In the proposed coherent λ switch, the tunable wavelength filter function is accomplished using coherent optical detection with a wavelength tunable local oscillator. The coherent photonic WD switching system has the following features; (1) low crosstalk switching for dense WDM signal, and (2) large line capacity capability. Design considerations show that 32 wavelength division channels can be available with a coherent λ switch. It is also shown that a broadband metropolitan-area-network with over 1000 line capacity is possible, using a multistage connection in the coherent λ switches. The switching function of the coherent λ switch is demonstrated in a two-channel wavelength-synchronized switching experiment, using 8-GHz-spaced, 280-Mb/s optical FSK signals     

电视发射机应急主备机天线倒换系统

1问题的提出湖南电视台于1987年和1988年先后向鞍山广播器材厂购买了1kW和10kW两台分米波27ch发射机,目前1kw机作为10kW机应急备分使用,两台发射机安装播出时未安装天线倒换系统。这样,当一台发射机出现故障,倒换到另一台发射机播出时需要花费5~7min,因此,造成了较?..     

Network and system concepts for optical packet switching

An overview of the characteristics and challenges of optical packet switching is given, illustrating its potential advantages within future nodes and networks, describing basic system functionalities. The opportunities introduced by the ACTS KEOPS project on all-optical packet-switching networks are highlighted, based partially on the outcome of the RACE ATMOS project, which is also considered in this article     

一种平均电流控制型开关调节系统的建模

文中对BUCK型DC_DC变换器进行了系统建模。为了得到包含平均电流调节开关控制方式的双环控制系统的简化模型,提出了一种电流环闭环传递函数的近似函数,并分别对电流控制器,电流补偿网络和功率级进行了建模,采用Mathcad进行仿真,得到系统相位裕度达到54°的结果。     

光纤自动切换保护系统的应用探讨

分析光纤自动切换保护系统的原理,以我公司为例,在光传输网络主要路由上,接入光纤自动切换保护器,利用保护器构建出光纤保护网络,当被保护的光纤发生故障中断或者衰耗增大导致通信传输质量下降时,光纤线路自动切换保护技术却能使网络进行实际切换,用恢复机制作为第二道防线对付网络范围的故障和失效,恢复通信的畅通,从而增强了我公司通信网络的可靠性。     

HYPASS: an optoelectronic hybrid packet switching system

An architecture is presented for an optoelectronic hybrid packet switching system (HYPASS) for the distribution of multiple-bit-rate broadband services. HYPASS is based on an input-buffered/output-controlled arbitration protocol. The internal routing and interconnection utilizes a passive optical transport network with wavelength-tunable laser transmitters and fixed wavelength receivers. The single-stage multiwavelength optical interconnect provides an internally nonblocking network for large throughput routing of the bit-serial optical signals. An internal optical control network, with fixed-wavelength trouble receivers, sends output port information to the input nodes for arbitration and control. Packet buffer storage and control processing is performed by word-parallel electronic circuitry. The characteristics and device requirements for this design are presented along with results of a performance analysis of the arbitration and control protocol