最新刊期
      卷 ， 期 1 ， 1987
      • Gu Yuhua Wang Zhenying
        Issue 1, Pages: 1-8(1987) DOI: 10.13756/j.gtxyj.1987.01.001
        摘要：This paper describes the 5B6B coding strategy and synchronous principle as well as the calculation of synchronous performance by laying the key emphasis on "word disparity", which was first employed in China as transmission pattern on Wuhan 8 Mb/s Optical Fiber Communication System. Results show that the synchronous reliability is good. The occurence of misalignment due to BER = 10-3 is once every 1.2×1025 years on average. The alignment aquisition time is 466 μs, and a misalignment can be detected in 59 μs with a probability of 0.99.  
          
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      • Issue 1, Pages: 2-3(1987)
        摘要：<正> “中国光纤通信线路分布示意图”的按语现在,我国的光纤通信技术已趋于成熟,开始步入应用推广时期。到1986年底,全国已敷设公用通信网光缆线路近700km,安装了约30个光纤通信系统。其中,北京、上海、武汉、广州等地有多个光纤通信系统已投入使用。当然,就线路长度而言,多为短距离的。预计“七五”期间还要敷设4000km长途光缆线路。这些线路有的已着手敷设。  
          
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      • Yang Tongyou
        Issue 1, Pages: 9-16(1987) DOI: 10.13756/j.gtxyj.1987.01.002
        摘要：The importance and representations of the reliabilities of optical fiber communication lines are discussed. At the present stage, in order to obtain the desired creteria of the reliabilities,a standby system is essentially needed for optical fiber communication lines. By using the line code, the reliability will be much kigher than that of the conventional PCM multiplexing when drop/inset channels are needed by the repeater.  
          
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      • Ling Deji Chen Guocong
        Issue 1, Pages: 17-23(1987) DOI: 10.13756/j.gtxyj.1987.01.003
        摘要：The power spectral density of several mBnB codes are calculated,which are usually used in optical fiber communication systems. Comparasion has also been made with the spectral results for some 5B6 B coding tables.  
          
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      • Zhang Xinshe Zhou Wenjun
        Issue 1, Pages: 24-32(1987) DOI: 10.13756/j.gtxyj.1987.01.004
        摘要：Two different treatments are used for boundary condition in double-cladded monomode fiber. The dispersion charactristics of these fibers are studied in detail by means of variation-finite element method and some significent results have been obtained.  
          
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      • Zhao Bo~ Zhao Bo-Xian Institute of Posts and Telecommunications
        Issue 1, Pages: 33-39(1987) DOI: 10.13756/j.gtxyj.1987.01.005
        摘要：It is of the key importance to choose the parameter s/r for the design of the light coupling from a laser diode into a multimode fiber with spheric end. This paper discusses a method by which the optimal radious of curvature of the spheric-lensed fiber roptim and the optimal distance from the endface of the fiber to the light source soptim can be rather easily found. In this method the analytic expressions of γmin and （y/r） γmin are derived because y/r is adopted as the variable, therefore, the parameter （s/r）optim can be determined precisely.  
          
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      • Xu Jie
        Issue 1, Pages: 40-48(1987) DOI: 10.13756/j.gtxyj.1987.01.006
        摘要：Spectral properties of SWFM and equivalent-width PFM pulse trains are analysed.Fourier series expressions of the two pulse trains are deduced. Compared with several PFM plans,PFM plan of double frequency mode has the advantages of both SWFM and the equivalent-width PFM plans, thereby, it is a good transmision plan for optical colour TV transmission of short and medium distances.  
          
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      • Zhou Linsen Yang Xinmin Dai Rong
        Issue 1, Pages: 49-56(1987) DOI: 10.13756/j.gtxyj.1987.01.007
        摘要：It has been theoretically derived that the far field is also a Gaussian distribution provided that the near field on the output end face of single mode fiber is Gaussian distribution. Based on the obtained theoretical result, a new single mode fiber mode field diameter measuring technique by axially moving the aperture is suggested. Practical measurement shows that the result is quite satisfactory.  
          
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      • Issue 1, Pages: 56-57(1987)
        摘要：An experiment by means of low-loss single mode fiber at 1.55μm has been conducted. The LD is modulated by 140Mb/s PRBS. The repeater spacing comes to 60.5km. It provides an experimental basis for the exploitation of 1.55μm window and the increase of system capacity as Well as WDM technique.  
          
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