Radio Astronomy and Spectrum Management: The Impact of WARC-79

As a valid use of the radio spectrum and an official radio service, radio astronomy was very much a part of the 1979 World Administrative Radio Conference (WARC-79). The allocation of frequency bands is vitally important for the sustained health of the science. WARC-79 provided first the impetus for astronomers, worldwide, to examine the allocation requirements of radio astronomy and then the opportunity to communicate those needs to the regulatory community. The characteristics of radio astronomy, the criteria for interference-free operation, possibilities for sharing with other radio services, and the need for frequency-band allocations are discussed because all bear directly on an evaluation of the Conference. The Final Acts of WARC-79 are examined from the viewpoint of their impact on radio astronomy.     

The Impact of WARC-79 on the Broadcasting-Satellite Service

The World Administrative Radio Conference, Geneva, Switzerland, 1979 (WARC-79) decided many of the international issues facing the Broadcasting-Satellite service (BSS) and adopted Resolutions and Recommendations dealing with most of the others. This paper identifies the BSS issues considered at WARC-79, describes the actions taken during the Conference, indicates the current status of subsequent WARC-mandated activities involving the BSS, and assesses the potential impact of the WARC on future BSS systems.     

WARC-79 Changes to the Technical Radio Regulations

The WARC-79 met to revise and reorder the International Radio Regulations. This encompassed consideration of some 1300 pages of text over a two and one third month period by approximately eighteen hundred people. Approximately fourteen thousand proposals were presented. Technical proposals were considered within Committee 4 which was chaired by N. Morishima of Japan. This paper will identify those sections of the Radio Regulations considered in the Technical Committee, the important changes, and the implications thereof.     

The Impact of WARC-79 on Space Applications

Prior to the 1979 World Administrative Radio Conference (WARC-79), no frequency bands were allocated for remotesensing measurements. Actions taken by the WARC insure that frequencies will be available for such use, and that operations can be conducted without harmful interference on a worldwide basis for the benefit of all nations. Allocations employed for transfer of scientific data from spacecraft in all regions of space from near-Earth orbit to deep-space planetary ranges were significantly improved. New global allocations for Earth exploration-satellites will permit worldwide acquisition of Earth exploration data both via direct transmission and via relay satellites. New allocations for meteorological satellite data transmission will permit wide-band applications such as direct reception of highresolution picture data by users. Satellite-aided search and rescue systems will benefit from WARC decisions to allocate frequencies exclusively for emergency radiobeacon systems using space techniques. Bands to provide links between the satellite and Earth were designated for distress and safety operations. Time and frequency services with accuracies in the 10- to 50-ps range, needed to meet future system requirements for precise time and frequency information, will be possible because of WARC actions to allocate frequency bands with suitable bandwidth for these services. The search for communications from extraterrestrial intelligence was afforded a degree of protection near several spectral lines of basic physical interest.     

基于盲源分离的短波频谱管理监测研究

常规无线电频谱监测中,对同频段频谱相互重叠的混合信号缺乏有效的监测手段,盲源分离能在不需要已知源信号和传播信道的情况下,实现对接收混合信号的分离,得到纯净的源信号,是实现监测这种混合信号的有效方法,所以考虑将盲源分离应用到频谱管理监测中。介绍了盲源分离的基本概念,对短波频谱管理监测的盲源分离算法进行了分析,着重对该技术在电磁频谱管理监测中的应用进行了仿真,为频谱管理监测提供了技术支持。     

Impact of WARC-79 on the Studies of International Radio Consultative Committee (CCIR)

The CCIR provided the main technical bases for the World Administrative Radio Conference, 1979, including terminology; technical bases for allocation, regulation, and for the provision for new services; characteristics of equipment and emissions; radio wave propagation and noise data. The WARC specified CCIR studies to be carried out for a number of future radio conferences to be held in the 1980-1986 time period, including a conference in 1983 to plan satellite broadcasting in the region of the Americas and a world conference in 1984/1986 concerning the geostationary satellite orbit. Additional studies set out for technical radio regulations included, for example, determination of coordination area around an Earth station in the bands from 1 to 40 GHz shared between space and terrestrial services, and other technical criteria for frequency band sharing. Over the next few years, because of the intense schedule of ITU administrative radio conferences, CCIR studies related to frequency sharing and other radio regulations will increase markedly.     

Satellite Beam Optimization for the Broadcasting Satellite Service

In view of the forthcoming ITU Regional Administrative Radio Conference for the planning of the Broadcasting Satellite Service at 12 GHz for the American Continent to be held in 1983, there is a need for a means to transfer the service quality requirements for a Broadcasting Satellite Service into a consistent set of satellite and receiving terminal parameters.     

卫星多媒体数据广播业务分析及实现

首先简要分析了卫星多媒体数据广播业务的市场及其应用环境,接下来介绍了其技术和商业特点、实现的方法,最后阐述了卫星多媒体数据广播的市场策略及其相关的资金投入与成本牧益。在介绍卫星多媒体数据广播业务的实现方法时,具体说明了卫星多媒体广播的价值链、平台的功能要求、内容的创建以及技术平台的实现等。     

交互式移动多媒体广播业务的购买与保护

介绍了在交互式移动多媒体广播中起关键作用的服务购买与保护技术IPDC SPP,它专门针对资源受限的移动终端进行了优化.其中重点介绍遵从该规范的OSF机制,包括OSF的流程以及架构.最后介绍一种符合OSF规范的J2ME平台上的AES加密算法.     

紧急广播概况及我国开展紧急广播业务的相关建议

紧急广播是一种利用广播通信系统向公众通告紧急事件的业务,自从美国911事件后,各国逐渐重视这项广播业务.本文介绍了美国、欧洲和日韩的紧急广播概况,以及我国针对突发事件应对机制颁布的法令.根据国外现有紧急广播系统的特点和我国相关法令对紧急广播的要求,对我国将来开展紧急广播业务提出相关建议,供决策者参考.     

播出系统的科学管理

通过对播出系统现有设备的构成分析，针对播出设备在常规使用中所存在的一些故障隐患，提出系统设备构成的改进方案，说明加强播出系统的科学化规范化管理对确保安全优质播出的重要作用。     

多功能HF雷达海洋回波谱模拟软件

介绍了一种多功能的ＨＦ雷达海洋回波谱模拟软件，该软件是基于Ｂａｒｒｉｃｋ一阶，二阶ＨＦ雷达海洋散射截面方程并考虑了影响海洋因波Ｄｏｐｐｌｅｒ谱的多个因素编制而成的。     

浅议广电客服的发展与完善

结合张家港广电信息网络有限公司客服中心实际情况,提出广电客服改进的措施及如何提高客服人员的业务能力,使客户服务工作得到完善,最终让客户满意,从而进一步提升公司形象。     

播出系统的科学管理

通过对播出系统现有设备的构成分析 ,针对播出设备在常规使用中所存在的一些故障隐患 ,提出系统设备构成的改进方案 ,说明加强播出系统的科学化规范化管理对确保安全优质播出的重要作用     

短波低速数传系统扩频序列设计

扩频序列的设计是短波扩频体制数传系统的关键技术之一。介绍了短波扩频体制的数传系统模型,针对该系统中扩频序列的设计要求,研究了walsh序列和m序列的原理和构造方法,并利用这2种序列的优点,设计了一个新的复合序列。对walsh序列、m序列和新的复合序列的自相关性和互相关性进行了MATLAB仿真,通过对仿真结果的比较,得出该复合序列具有较好的相关特性,因此更能满足通信的需求。     

双多进制正交扩频在HF低速通信中的应用

双多进制正交扩频(Dual M-ary Orthogonal Spread Spectrum)技术是一种高频谱效率的扩频技术,而短波通信在通信领域具有其他通信手段无法替代的地位。阐述了双多进制正交扩频系统的基本原理,介绍了美军现役短波调制解调器标准MIL-STD-188-110B中的低速串行75 b/s波形。设计了基于双多进制扩频技术的短波低速改进波形,并与美军标MIL-STD-188-110B中的低速串行75 b/s波形进行了对比仿真。仿真结果表明,与美军标波形相比,改进波形的BER性能在AWGN信道及衰落信道下均有明显提升。     

基于中低速率短波扩频通信系统设计

文章提出了一种LDPC＋MFSK＋SSHF中低速短波扩频通信系统设计方案,采用Walsh正交扩频方式,MFSK调制方式和LDPC编码。该方案具有较好的鲁棒性,能够满足军事通信高可靠性的要求。     

基于FFT实现短波扩频系统载波频差估计

短波扩频系统中,由于伪码速率低,加上频率源不稳定及多普勒频移的影响,收发端载波往往存在一定频差,使得PN码无法同步。针对这种情况,提出了对正交下变频后I,Q两路信号相乘的结果做快速傅立叶变换来估计频差的方法。这种方法简单易行,且不受PN是否同步的影响,可以把收发端载波频差控制在很小的范围内。