共查询到19条相似文献,搜索用时 46 毫秒
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结合浙江传媒学院的实际情况,简述了高清数字新闻直播车的车体改装工艺要求、现场直播系统设计和卫星上下行链路的构成,实现了既能独自完成新闻节目录制和上星任务,又能与高清转播车级联组建大型电视直播系统. 相似文献
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本文以浙江广电集团好易购电视购物频道4+2讯道高清卫星转播车设计为基础,从设计思路、车体设计、系统及设备等方面探讨设计和建造满足电视购物业务需求的高清卫星转播车思路,分享“以高清技术为基础,实现高/标清同播及卫星传输”的电视购物高清卫星转播车设计经验. 相似文献
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本文结合设计集成卫星转播车的经验,详细介绍了卫星转播车的天线系统、视音频系统、通话系统、配电系统、车体载重平衡设计和建设体会,并对卫星转播车未来的发展趋势和应用前景做了探讨。 相似文献
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介绍了浙江卫视的新型卫星新闻转播车(DSNG)系统,分析了2008年“两会”直播方案技术特点,介绍了DSNG在“两会”直播报道中的应用。 相似文献
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Robert Howell Paul Thompson 《International Journal of Satellite Communications and Networking》1992,10(2):71-79
Measurements of slant-path attenuation and crosspolar discrimination, obtained from four satellite measurement programmes carried out at the BT Laboratories, Martlesham Heath, England, are described. The measurements covered frequencies in the range 11.3 GHz to 30 GHz, path elevations ranging from 8.3° to 29.9°, and were made using both circularly and linearly polarized signals. Cumulative distributions, derived from the measured data, are extrapolated to frequencies of 12.5, 14.3, 19.8 and 29.7 GHz and then combined to give statistics for a database of more than 20 years. 相似文献
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为了降低时间尺度的时间起伏标准偏差,对卫星时间尺度(GPS,GLONASS)的长期模型优化方法进行了评述,并对时间中心和时间实验室的数据分析进行了检验。结果表明,采用混合模型方法进行修正或控制,卫星时间尺度的长期时间起伏可变为白噪声过程:GPS时间尺度的时间起伏标准偏差可下降到10 ̄20ns,与一天内的短期结果接近,GLONASS时间尺度的结果大些,GLONASS时间尺度的时间起伏标准偏差的平均改 相似文献
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P. P. Nuspl R. Peters T. Abdel-Nabi N. Mathews 《International Journal of Satellite Communications and Networking》1987,5(2):65-76
This paper discusses on-board processing systems and associated benefits including connectivity, increased capacity, lower costs and system improvements; there are complex trade-offs in design approaches. Several architectures are described which use a microwave switch matrix, a baseband switch matrix or baseband processor. Regeneration (an advanced form of on-board processing) consists of demodulation followed by remodulation and provides access to baseband signals. The link advantages of this method are clearly presented for 120Mb/s TDMA and for IBS at 1/544 Mb/s. Additionally, there are discussions of five architectures using multi-carriers per transponder, and their advantages and disadvantages. Some considerations of using on-board decoding and baseband processing functions are also briefly presented. 相似文献
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P. T. Thompson R. Silk A. Herridge 《International Journal of Satellite Communications and Networking》1992,10(4):183-198
Developed primarily to provide continuation of services from the INTELSAT V satellites in the Pacific Ocean Region, this latest generation of satellites also has utility for operation in other roles. Several new technologies are combined to give cost-effective international satellite communications on a global, regional and domestic basis. This new higher power satellite will form a fundamental part of the INTELSAT global network, having been designed to match the projected traffic demands and future service requirements. 相似文献
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Giovanni Giambene Enrico Zoli 《International Journal of Satellite Communications and Networking》2003,21(2):199-225
In this paper, we investigate a packet access scheme that is able to support mixed traffics in the presence of high propagation delays. Referring to a Time‐Code Division Multiple Access air interface, we propose a Medium Access Control (MAC) protocol based on a random access scheme. A successful attempt grants the use of a slot‐code resource. This protocol is named Adaptive Time Code‐Packet Reservation Multiple Access (ATC‐PRMA), since the access parameters are changed, depending on the traffic load conditions, so as to fulfil Quality of Service requirements. Numerical examples are carried out for the Low Earth Orbit (LEO)‐Mobile Satellite System (MSS) scenario, but all these considerations could be applied to High‐Altitude Platform Stations (HAPSs) as well. In both cases, high propagation delays prevent an immediate feedback to users. An analytical approach is proposed to study the stability of our MAC scheme. Accordingly, we define a criterion for optimizing system performance. The predicted ATC‐PRMA behaviour is supported by simulation results. Finally, we show the performance improvement of ATC‐PRMA with respect to a MAC protocol not employing adaptive parameters. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献