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利用特征矩阵法研究了多腔薄膜梳状滤波器在C波段的透射峰在入射角微小变化中的变化规律,结果表明:在入射角缓慢增大的过程中,各透射峰的位置逐渐向短波方向移动,各透射峰的形状周期性地变化;随着入射角的增大,透射峰个数减少,透射峰变宽,透射峰的位置和形状变化加快,以至于极小的入射角变化就会使透射峰的位置和形状产生很大的变化。 相似文献
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The paper describes the main characteristics of the transmission networks that are used in the urban and rural areas. Existing principles of the urban and rural transmission networks' creation are given. The subscriber transmission network is considered. The St. Petersburg transmission network is analyzed as an example of an urban transmission facility. Aspects related to commercial network creation are briefly discussed 相似文献
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针对采用短波和超短波通信方式设计的发信浮标通信可靠性差,结构设计复杂,使用不便等缺点,提出一种基于Inmarsa-C系统设计的发信浮标系统。该系统采用Inmarsat-C卫星用户终端作为发信设备,采用Atmel公司的AT89C51单片机实现发信控制,其特点是发信可靠,功耗小,体积小,重量轻。对系统的硬件电路、软件设计进行了介绍。实验结果显示,基于Inmarsat—C卫星用户终端设计的发信浮标在水中摆动角度不大于60°、摆动频率不大于10Hz时,可正常发信。信息从发送终端到接收终端的延迟时间因发送方式和发送数据量的不同而有差别,大致在40s~5min的时间范围内。 相似文献
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Montejo-Garai J.R. Ruiz-Cruz J.A. Rebollar J.M. Padilla-Cruz M.J. Onoro-Navarro A. Hidalgo-Carpintero I. 《Microwave Theory and Techniques》2005,53(5):1636-1642
In this paper, an extension to the extracted pole technique for synthesizing N-order filters with N-transmission zeros at real frequencies is presented. In addition, a new bandpass rectangular waveguide H-plane low-cost configuration filter for high-power low-loss application (patent pending) that implements a filtering function with finite real frequency transmission zeros is proposed. This structure operates as a resonant cavity in transmission at central frequency of the bandpass and simultaneously introduces a controlled transmission zero out of the bandpass. Since every double-controlled electrical behavior cavity introduces a transmission zero, it is possible to introduce as many transmission zeros as the order of the filtering function. In order to validate the synthesis procedure and the new structure, different filters have been designed: a second-order filter with two transmission zeros, a third-order filter with one transmission zero, a fourth-order filter with two transmission zeros, and finally, an eighth-order filter with two transmission zeros. The last two have been manufactured, showing an excellent agreement between the measurement and theoretical simulation. 相似文献
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为设计高效光滤波、光放大、光衰减和光开关等新型量子光学器件,用传输矩阵法理论研究了一维光子晶体(AB)m(AABAABAABAA)n(BA)m的光传输特性,结果发现:在实介电常量或复介电常量情况下,光子晶体均构成光量子阱结构,并呈现明显的量子化效应,实介电和复介电常量量子阱的透射谱结构与特点相同,透射峰数目和频率位置均与周期数n 密切相关;当折射率nB为含负虚部的复介电常量时,光量子阱的共振透射峰出现不同程度的透射增益、放大现象,增益倍数最高达103 数量级,同时共振透射峰频率处出现很强的受激辐射,辐射极强达到104数量级;当n3 时,随n的增加量子阱透射增益倍数呈现下降趋势,共振透射峰频率处的受激辐射也随之下降;当nB为含正虚部的复介电常量时,共振透射峰则出现明显地透射衰减现象。这些特性为实验制备工作提供理论依据和指导。 相似文献
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本文从估量的角度入手,分析数字微波的传输特性。在弄清概念的基础上,着重于实际电路传输质量的估算,为电路设计,提高广播电视传输质量提供依据。 相似文献
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Jing Deng Han Y.S. Po-Ning Chen Varshney P.K. 《Communications, IEEE Transactions on》2007,55(9):1772-1782
The transmission range that achieves the most economical use of energy in wireless ad hoc networks is studied for uniformly distributed network nodes. By assuming the existence of forwarding neighbors and the knowledge of their locations, the average per-hop packet progress for a transmission range that is universal for all nodes is derived. This progress is then used to identify the optimal per-hop transmission range that gives the maximal energy efficiency. Equipped with this analytical result, the relation between the most energy-economical transmission range and the node density, as well as the path-loss exponent, is numerically investigated. It is observed that when the path-loss exponent is high (such as four), the optimal transmission ranges are almost identical over the range of node densities that we studied. However, when the path-loss exponent is only two, the optimal transmission range decreases noticeably as the node density increases. Simulation results also confirm the optimality of the per-hop transmission range that we found analytically. 相似文献
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This paper reviews the status of research and development in both microwave radio-relay systems and millimeter-wave transmission systems as well as the technical features in these fields, mainly developed under the auspices of Nippon Telegraph and Telephone Public Corporation (NTT). Recent activities have been the development of new solid-state devices and high-capacity systems. The application of solid-state techniques is being extended to systems of both analog and digital transmission, such as the 2700 multichannel telephone transmission system in frequency division multiplexing (FDM)-FM radio-relay system, an experimental 20-GHz PCM radio-relay system capable of 400 Mbits/s pulse transmission, and a guided millimeter-wave system of 800-Mbit/s transmission at 40-80 GHz. The microwave integrated circuit (MIC) is also becoming very important in utilizing these high-frequency regions, which should be a valuable resource in the future when a vast information transmission capability will be required. 相似文献
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有线电视视频传输技术作为视频行业的技术领航,专注于视频传输服务50余年,视频传输网络建设、视频处理能力、客户服务体系、安全传输需求等方面都已经形成了自己的一整套解决方案。基于此,就天网工程建设中应用到的相关视频传输技术和组网架构进行了阐述,就EPON技术在解决天网工程中视频传输及应用方面存在的难点提出了创新的解决思路,并在实践中实现良好的效果,从而为有线电视视频传输技术在城市信息化建设的应用给出了建议和参考方案。 相似文献
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周天 《电信工程技术与标准化》2005,(7):19-23
本文分析现阶段超长距离光传输技术的功能特点和需要解决的问题,展开讨论了多项技术革新带来的新动向.提出超长距离光传输技术现阶段只适用于部分区域,并展望在将来全国干线传输网中超长距离光传输将发挥重要作用. 相似文献
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针对雷达高速数据传输的需求,提出一种实现简单、可靠性高的解决方案。该方案应用W7100网络微处理器实现雷达高速数据通信接口。介绍了W7100芯片的结构和特点,阐述了数据传输接口的硬件设计、配置软件和通讯软件设计,详细说明了UDP方式的数据传输流程。实验表明该接口工作稳定,传输速度高,能够很好地满足雷达数据高速传输要求。 相似文献
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为了增加光电平台有效载荷的放置空间,需要将其内框架布局进行合理优化。采用平行轴传动方式,将光电编码器安装在主轴旁,可有效扩大光电平台内框架轴向空间。分析了同心轴传动和平行轴传动的优缺点,在平行轴传动中,阐述了单片齿轮传动、消间隙齿轮传动及钢带传动的适用性与局限性。通过实验分析了消间隙齿轮传动与钢带传动在有限转角范围内对光电编码器测角精度的影响。实验结果表明,消间隙齿轮传动在有限转角范围内的测角误差大于3,钢带传动在有限转角范围内的测角误差小于1,为增加有效载荷空间提供了一种途径。 相似文献