DOI:10.1049/ree.1984.0042

出版商:IERE    

年代:1984

数据来源: IET

摘要:

This paper outlines some of the different types of digital radio relay systems that are now in worldwide service, identifies the factors which contribute to their performance, and illustrates the performance standards that are currently being achieved.The CCIR performance standards for high capacity digital radio systems are discussed, together with some of the system planning guidelines in current use, and these are compared with worldwide results from a number of system field evaluations. The comparison shows that the CCIR standards can be achieved on established microwave networks, using advanced equipment designs which incorporate diversity and adaptive equalizers to overcome the effects of dispersive fading.The performance and availability of medium and lowcapacity systems are also briefly reviewed, and predictions of non-availability due to rainfall fading are given for some typical systems.The paper concludes that the performance standards for digital radio systems will be in accordance with the highest quality grades required for transmission media in an Integrated Services Digital Network.

DOI:10.1049/ree.1984.0043

出版商:IERE    

年代:1984

数据来源: IET

摘要:

Following a table of typical system parameters, this paper seeks to address specific design aspects of long-haul digital submarine systems utilizing optical fibre bearer pairs. These aspects include· Reliability· Error performance specification and design philosophy· Receiver design, noise and intersymbol interference considerations· Jitter accumulation and control· Telemetry, supervision and fault locationNo such systems have yet been deployed other than for field trial but development is well advanced. The first systems should be deployed during the latter half of 1984.

DOI:10.1049/ree.1984.0044

出版商:IERE    

年代:1984

数据来源: IET

摘要:

The paper reviews the developments which have taken place in digital transmission of vision and sound signals. The transmission impairments are related to the requirements for broadcast quality signals and the further developments needed to achieve satisfactory economics are considered.

DOI:10.1049/ree.1984.0046

出版商:IERE    

年代:1984

数据来源: IET

摘要:

This paper considers the theoretical and practical aspects of the design of digital optical fibre systems with particular emphasis on system performance. The requirements of the International Standards and how they relate to actual system performance specification are then discussed. Finally the operational experience obtained to date is summarized.

DOI:10.1049/ree.1984.0047

出版商:IERE    

年代:1984

数据来源: IET

摘要:

The paper starts with a summary of the techniques available for implementing digital satellite transmission systems, then goes on to discuss current and probable new error performance objectives that will be consistent with the requirements of the Integrated Services Digital Network (ISDN). The main body of the paper discusses factors which affect performance, including capacity/quality trade-offs, satellite and Earth station parameters, atmospheric propagation conditions, interference and intermodulation. The conclusion indicates briefly the techniques available to a system designer to meet performance requirements.

DOI:10.1049/ree.1984.0048

出版商:IERE    

年代:1984

数据来源: IET

摘要:

Consideration is given to the design and performance of transmission systems operating over metallic cables for use in different parts of the telecommunication network. Particular attention is given to thermal noise, crosstalk, and impulsive noise limited systems in the context of achieving an acceptable error performance. A methodology of performance specification is discussed and the importance of providing immunity against so-called ‘network effects’ is emphasized. The status of international studies with respect to the performance specification of digital line systems is reviewed. The actual error performance of some operational and field trial systems is reported and error clustering is found to be significant on some systems.

DOI:10.1049/ree.1984.0050

出版商:IERE    

年代:1984

数据来源: IET