2,156 research outputs found

    Sharing the 620-790 MHz band allocated to terrestrial television with an audio-bandwidth social service satellite system

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    A study was carried out to identify the optimum uplink and downlink frequencies for audio-bandwidth channels for use by a satellite system distributing social services. The study considered functional-user-need models for five types of social services and identified a general baseline system that is appropriate for most of them. Technical aspects and costs of this system and of the frequency bands that it might use were reviewed, leading to the identification of the 620-790 MHz band as a perferred candidate for both uplink and downlink transmissions for nonmobile applications. The study also led to some ideas as to how to configure the satellite system

    Back to the Future: The Emergence of Contrasting European and US Approaches to Digital Radio

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    Digital radio has been in development for over 25 years and yet is no nearer a point of successful adoption. This paper explores the emergence of contrasting European and American approaches to digital radio. The most established of these, Eureka-147 or Digital Audio Broadcasting (DAB), which originated in Europe, is contrasted with the so-called IBOC or /HD Radio approach, as alternative collective conceptualizations of how technology can bridge contemporary broadcasting practice to an ̳imagined‘ digital future. Drawing on the concept of ̳symptomatic technology‘ (Williams 1974), DAB‘s origins in European R&D policy of the 1980s and its affinity with established European broadcasting practice is characterised as a distinct technological vision for how the frontiers for radio broadcasting could be expanded within the European political and cultural landscape of the time. DAB‘s attempt to map a global solution for digital radio, combining satellite and terrestrial broadcast strategies, met with significant US opposition which subsequently supported the development of the alternative ̳in-band, on-channel‘ approach. While neither solution is guaranteed long term success, their importance lies in the mobilization of the relevant national and international policy frameworks for the construction of radio‘s future. Paying close attention to the discourses of technology inherent in these approaches and drawing on relevant contemporary engineering and technical descriptions, this analysis seeks to complement social shaping of technology studies (Mackay and Gillespie 1992) by focussing on the promotional efforts designed to support a particular technology‘s adoption

    Applications of satellite technology to broadband ISDN networks

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    Two satellite architectures for delivering broadband integrated services digital network (B-ISDN) service are evaluated. The first is assumed integral to an existing terrestrial network, and provides complementary services such as interconnects to remote nodes as well as high-rate multicast and broadcast service. The interconnects are at a 155 Mbs rate and are shown as being met with a nonregenerative multibeam satellite having 10-1.5 degree spots. The second satellite architecture focuses on providing private B-ISDN networks as well as acting as a gateway to the public network. This is conceived as being provided by a regenerative multibeam satellite with on-board ATM (asynchronous transfer mode) processing payload. With up to 800 Mbs offered, higher satellite EIRP is required. This is accomplished with 12-0.4 degree hopping beams, covering a total of 110 dwell positions. It is estimated the space segment capital cost for architecture one would be about 190Mwhereasthesecondarchitecturewouldbeabout190M whereas the second architecture would be about 250M. The net user cost is given for a variety of scenarios, but the cost for 155 Mbs services is shown to be about $15-22/minute for 25 percent system utilization

    High definition systems in Japan

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    The successful implementation of a strategy to produce high-definition systems within the Japanese economy will favorably affect the fundamental competitiveness of Japan relative to the rest of the world. The development of an infrastructure necessary to support high-definition products and systems in that country involves major commitments of engineering resources, plants and equipment, educational programs and funding. The results of these efforts appear to affect virtually every aspect of the Japanese industrial complex. The results of assessments of the current progress of Japan toward the development of high-definition products and systems are presented. The assessments are based on the findings of a panel of U.S. experts made up of individuals from U.S. academia and industry, and derived from a study of the Japanese literature combined with visits to the primary relevant industrial laboratories and development agencies in Japan. Specific coverage includes an evaluation of progress in R&D for high-definition television (HDTV) displays that are evolving in Japan; high-definition standards and equipment development; Japanese intentions for the use of HDTV; economic evaluation of Japan's public policy initiatives in support of high-definition systems; management analysis of Japan's strategy of leverage with respect to high-definition products and systems

    Space industrialization. Volume 4: Appendices

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    Program development and analysis and recommendations for NASA activities are discussed. The impact of international space law on future use of outer space is examined in the light of applicable international agreements. Recommendations for actions designed to facilitate space industralization are also proposed

    Radio Frequency Interference Impact Assessment on Global Navigation Satellite Systems

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    The Institute for the Protection and Security of the Citizen of the EC Joint Research Centre (IPSC-JRC) has been mandated to perform a study on the Radio Frequency (RF) threat against telecommunications and ICT control systems. This study is divided into two parts. The rst part concerns the assessment of high energy radio frequency (HERF) threats, where the focus is on the generation of electromagnetic pulses (EMP), the development of corresponding devices and the possible impact on ICT and power distribution systems. The second part of the study concerns radio frequency interference (RFI) with regard to global navigation satellite systems (GNSS). This document contributes to the second part and contains a detailed literature study disclosing the weaknesses of GNSS systems. Whereas the HERF analysis only concerns intentional interference issues, this study on GNSS also takes into account unintentional interference, enlarging the spectrum of plausible interference scenarios.JRC.DG.G.6-Security technology assessmen

    A study of worldwide communications markets: The relationship between federally sponsored research and development and competitiveness of US industry in this market

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    Many factors have been reviewed in an attempt to seek criteria for the establishment of regions or nations as potential customers for space communication systems. These include economic measures, demographic distributions, topographic variations, physical size, national dispersion, telephones available, investment credit viability, and the general level of technology within the population. A major consideration is the fact that essentially all nations are subject to significant financial constraints. Consequently, some form of national investment priorities becomes necessary, and these priorities are generally perceived differently according to the factors mentioned above and also according to the personalities and interests of each nation's decision makers
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