DOI:10.1049/ecej:19900011

出版商:IEE    

年代:1990

数据来源: IET

摘要:

Array antennas were used in early radar systems. Today's microwave phased arrays with electronic beam-steering allow surveillance and tracking with variable data rates in a multifunction radar. The paper reviews system options and discusses the engineering of active arrays, using as an example the Siemens Plessey Radar/ARE MESAR, which is now undergoing trials and which is the first modular active array radar in the UK. Future applications, the success of which depends on cost-effective production of active transmit–receive modules, improved beam control, and larger wideband arrays, are outlined.

DOI:10.1049/ecej:19900016

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The paper presents a brief review of the historical developments which have resulted in the emergence of secondary surveillance radar (SSR) and, most recently, of Mode S as the principal radar sensor worldwide for civil air traffic control. The essential technical characteristics of both SSR and of Mode S are described.

DOI:10.1049/ecej:19900017

出版商:IEE    

年代:1990

数据来源: IET

摘要:

One of the most important factors affecting the technical quality of a television picture is the amount of noise, or ‘snow’, on the picture. A television receiver produces noise if the signal from the antenna is weak, and the weaker the signal, the greater the amount of noise that is produced. Methods of predicting and measuring the signal strength are well established, but there appears to be no satisfactory reference in the literature describing what happens in the television receiver, and therefore this paper attempts to clarify and quantify the noise-related aspects of the performance of a television receiver. Following this, the study is extended to the antenna system, allowing us to show that the CCIR minimum field strengths are applicable in the context of modern receiving installations.

DOI:10.1049/ecej:19900018

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The background to second generation cordless telephony (CT-2) is set out to show the relationship between telepoint and cellular radio services. The physical layer of the telepoint air-interface is described with justification of the technical choices made in working towards the common air-interface which will supercede initial proprietary standards. The various channels and signalling multiplexes are then discussed in sufficient detail to permit understanding of the procedures by which portable terminals establish connections through base stations to the public switched network. The paper concludes with an optimistic projection of the future for telepoint services in the UK and other European countries.

DOI:10.1049/ecej:19900022

出版商:IEE    

年代:1990

数据来源: IET

摘要:

Optical fibre is rapidly becoming the preferred transmission medium for both telecommunication and datacommunication networks. However, the deployment of optical systems in high-density local-area networks can enhanced by the use of low-cost architectures and components. Bidirectional networks, in which send and receive signals are carried simultaneously on a single fibre, offer the possibility of reduced fibre costs. However, to fully exploit this technique it will be necessary to employ transceiver modules consisting of an optical transmitter and receiver colocated in the same package. The paper describes a low-cost optical transceiver module that is capable of supporting full duplex transmission on singlemode optical fibre.

DOI:10.1049/ecej:19900023

出版商:IEE    

年代:1990

数据来源: IET