DOI:10.1049/ecej:19920059

出版商:IEE    

年代:1992

数据来源: IET

摘要:

Asynchronous transfer mode (ATM) has emerged as a possible contender for the next generation switching system and fundamental transport basis for the broadband integrated services digital network (B-ISDN) and telecommunications in the future. It is widely thought of as the network to accommodate the uncertain requirements of future public communications because of its high degree of flexibility and service independency. The Orwell protocol developed by British Telecom can provide a communication base to meet the requirements of such a network. Orwell is used here as a slotted ring protocol designed to carry a mixture of services which form the basis of an ATM network. The paper describes the realisation of a 155.52 Mbit/s fibre-optic physical layer from the Orwell protocol based on an ATM technology, and also discusses how the Orwell protocol can offer broadband transport capabilities and can provide access to and interwork with existing networks, such as telephone networks and 64 kbit/s based ISDNs.

DOI:10.1049/ecej:19920063

出版商:IEE    

年代:1992

数据来源: IET

摘要:

The paper reviews many of the coding techniques which have been proposed for use in spread-spectrum communication links. In these systems, narrow-band data accesses a common wideband channel, with each subscriber assigned to a unique access code. This code division multiple access (CDMA) system permits uncoordinated access to the channel with the interference level set by the total number of active subscribers. The paper investigates pseudo-noise (PN) and related sequence sets, specifically the auto- and crosscorrelation responses are examined both with and without data transmissions. These are quantified in terms of peak sidelobe errors, characteristic probability density functions and bit error ratio performance in the CDMA multi-user traffic environment. This allows the CDMA capacity to be predicted given the bit rate requirements, total available bandwidth and required bit error ratio

DOI:10.1049/ecej:19920064

出版商:IEE    

年代:1992

数据来源: IET

摘要:

A variety of solid-state devices are being developed for use in systems where they are required to produce pulses of microwave power at specified duty cycles. The design of these devices is interesting as they will be smaller and have less thermal capacity than an equivalent continuous-wave source generating the same microwave power. This size reduction is important as it can result in improved electrical efficiency and a higher frequency of operation. The paper describes the application of transmission line matrix diffusion modelling to the transient thermal design of a transistor structure and compares the technique with finite difference and finite element approaches.

DOI:10.1049/ecej:19920065

出版商:IEE    

年代:1992

数据来源: IET

摘要:

In recent years broadcast video technology has begun to shed its analogue history and take on board the benefits of the digital era. Areas such as digital video recording and processing have been addressed. However, until now, the means of conveying digital video information from one device to another have been cumbersome and expensive. The article describes how these problems have been overcome. It describes the limitations of the current method and provides an overview of a new, serial, interface. Details and benefits of the new interface are given and new integrated circuits to implement the interface are also described. Consideration is given to installation, test and measurement.

DOI:10.1049/ecej:19920066

出版商:IEE    

年代:1992

数据来源: IET

摘要:

The paper indicates, for the benefit of system designers, how and to what extent independently available information — or generic characteristics derived from the signal itself — can be used to enhance the extraction of wanted signals in the presence of noise or interference. To bring out the commonalities in apparently different problems or methods, it uses the ‘state-space’ concept, common to the dimensions of time, frequency, antenna aperture and image space, and it treats signal processing as a sequence of transformations subject to a set of limiting constraints.

DOI:10.1049/ecej:19920067

出版商:IEE    

年代:1992

数据来源: IET

摘要:

Based in Basel, Switzerland, the RACE II project R2061, ‘EXPLOIT’, is making a major contribution towards achieving the RACE programme's aim of introducing integrated broadband communication (IBC) services on a European Community-wide basis by 1995. The paper describes the interconnectivity features that are being developed to enable interworking with other ‘broadband islands’, and the traffic experiments that will be performed to provide much-needed information from real sources on the ATM-sensitive areas of traffic control, resource management and performance.

DOI:10.1049/ecej:19920068

出版商:IEE    

年代:1992

数据来源: IET

摘要:

The aim of the European Community's RACE programme has been the introduction of integrated broadband communication services throughout the Community by 1995. Project R1022 is tasked with demonstrating the feasibility of a broadband network based on the asynchronous transfer mode (ATM). The paper considers the alternative ways of introducing ATM broadband networks into the existing European communications structure in a cost-effective manner which offers advantages to network operators and end users.

DOI:10.1049/ecej:19920069

出版商:IEE    

年代:1992

数据来源: IET

摘要:

The paper describes an application pilot experiment being carried out under the European Communities' RACE programme. The experiment centres on the electronic security industry, in particular the remote monitoring of alarm signals. The aim of the project is to reduce the waste of resources caused by the high number of ‘false’ alarm calls and to introduce the users of remote signalling systems to the benefits of improving communications technology. The paper summarises the problem and presents a scenario for introducing the users of basic signalling systems to a wider variety of potential services that can be provided in an integrated broadband communications environment.

DOI:10.1049/ecej:19920070

出版商:IEE    

年代:1992

数据来源: IET

摘要:

During the course of the last ten years optical transmission systems have more and more taken over the functions of their copper counterparts in the trunk network. However, replacement of copper-based transmission by optical-fibre-based transmission is only the first step in the utilisation of the large transmission capabilities of optical fibre.Deployment of optical fibres will penetrate further to the local loop to bring broadband and narrowband services directly to the customer. In the RACE 2024 project research is being undertaken towards a cost-effective broadband access facility (BAF) for the small business and residential customer and based on the asynchronous transfer mode (ATM). The paper highlights the characteristics of a suitable passive optical network to be used in the BAF system. Following an overview of the complete BAF system layout, attention is focused on the optical network, topology and realisation aspects.

DOI:10.1049/ecej:19920071

出版商:IEE    

年代:1992

数据来源: IET