摘要:

This paper describes measurements of frequency spectrum and amplitude of 5 GHz signals reflected from large, generally flat, building faces. Two techniques were used, namely dynamic (i.e. fast moving transmitter source) and static, with ground-based equipment located near an aircraft runway. Although simple theoretical considerations had suggested that the reflection characteristics should be approximately specular, the results showed that there were both spectrum broadening and large rapid fluctuations of reflection amplitude over the specular zone, with significant scattering outside this region.

DOI:10.1049/ree.1981.0009

出版商:IERE    

年代:1981

数据来源: IET

摘要:

This paper follows on from the previous paper in the series and attends to the methodology of design as conceived within the whole-system whole-life dimensions of systems engineering. It assumes the concepts and general structure of systems engineering as outlined in the previous paper and goes on to elaborate the form and content of systems engineering from a design perspective.The paper begins by considering the systems engineering organization within the hierarchical structure for project design and management that has evolved from the one-time individual project engineer. Then the important relationships between entrepreneur/contractor, customer/owner, user are explored to illustrate why design in the system engineer's hands is dominated by overall cost-effectiveness optimized with respect to the future whole-life operations. The systems engineering design process is very similar to multiple-objective decision analysis as both designer and decision maker are faced by a similar problem: to find a way of organizing action and deploying resources so that a desirable future state is realized efficiently. The decision analytical process is structured to provide a framework for the systems design methodology itself. This follows using a top-down (hierarchical) approach in which overall system worth is determined with respect to clearly articulated objectives and evaluated with respect to a comprehensive multiattribute value criteria. Cost-effectiveness is disaggregated into its components of availability, dependability, capability and discounted whole-life cost. These in turn are related to the sub-design problems of operational performance, reliability, maintenance, logistic support, risk and impact analysis.

DOI:10.1049/ree.1981.0010

出版商:IERE    

年代:1981

数据来源: IET

摘要:

A cellular array for the multiplication of signed binary numbers is presented. The implementation is based on the direct addition of the partial products. The addition of the negative partial products is performed with a new method which yields a fully cellular array. Furthermore, the proposed array multiplier has an iterative cell interconnection pattern and it is well suited for large-scale integration.

DOI:10.1049/ree.1981.0011

出版商:IERE    

年代:1981

数据来源: IET

摘要:

The paper discusses the addition of EBU time and control code to the twin-track format on 6.3 mm tape recorders. The code is carried on a centre track 0.8 mm wide using a recording characteristic of zero microseconds so that the system can read the code accurately over a wide range of tape speeds. To preserve the waveshape, the recording amplifier has phase-corrected equalization; and to minimize noise, the equalization of the reproducing chain is split into two parts using head loading for highfrequency compensation followed by a low-frequency circuit in the amplifier.

DOI:10.1049/ree.1981.0012

出版商:IERE    

年代:1981

数据来源: IET