最新刊期
      卷 ， 期 2 ， 1988
      • Chen Guocong
        Issue 2, Pages: 1-12(1988) DOI: 10.13756/j.gtxyj.1988.02.001
        摘要：This paper introduces design of 140Mb/s long distance optical cable communication systems. From system model selected, the lengths of hypothetical reference digital link and digital section are chosen, then the properties of bit error and jitter are determined. Based on the practicability of networks, two types of line code, 8B1H and 5B6B, are chosen, which are applied to two different systems. Furthermore, stress is laid on the approach to determine the major parameters of optical link and on the functions of auxiliary systems. Finally, the design of major specifications of data link for transmitting auxiliary signal by amplitude modulation of optical digital signal is introduced in detail.  
          
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      • Issue 2, Pages: 13-20(1988) DOI: 10.13756/j.gtxyj.1988.02.002
        摘要：This paper describes the major performance and applications of the PFM （pulse frequency modulat ion） optical fiber transmission equipment for colour TV programs with two accompanying sound channels.When the receiver sensitivity is-34.5dBm, the Grade-A Specifiations for Short Range Optical Cable Transmission GY-38-86 stipulated by the Ministry of Radio, Film and Television can still be satisfied.  
          
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      • Zhongdao Le,Hanxin Deng
        Issue 2, Pages: 21-29(1988) DOI: 10.13756/j.gtxyj.1988.02.003
        摘要：In this paper the imperfections of Asatani′s DP and DG compensation circuits are analysed and corrected。 A complete design approach is given for compensating the LED nonlinearity.  
          
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      • Zhang Zhibing
        Issue 2, Pages: 30-36(1988) DOI: 10.13756/j.gtxyj.1988.02.004
        摘要：A nonlinear DPCM Prediction coding approach is presented and its adaptive properties are discussed. By computer simulation experiments, very high signal to noise ratio and good subjective results with 1 bit/pel coding can be obtained. Its performance is remarkably improved and bit rate greatly reduced as compared with the predictor of Pirsh.  
          
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      • Zheng Jihuan
        Issue 2, Pages: 37-45(1988) DOI: 10.13756/j.gtxyj.1988.02.005
        摘要：This paper first expounds the twotime measurement method of the four methods for measuring the mode- field - diameter （MFD） of single-mode fibers,ane the implementation of these methods. Then a conclusion is drawn that the modified far-field rotating knifeedge method is the best among the four, based on analyses and comparisons.Finally, the experimental results are given.  
          
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      • Issue 2, Pages: 46-49(1988) DOI: 10.13756/j.gtxyj.1988.02.006
        摘要：This paper describes the improvements in quality of LPE wafers and in photo-electric charateristics of devices by adopting low temperature （as low as 560℃） two LPEs and elaborately photoetching, with the lowest threshold current of 17mA, single facet external differential quantum efficiency of 25%, maximum CW lasing temperature of 130℃, maximum output power of more than 30mW. The reliability of devices is enhanced by adopting PbSn welder and improved manufacturing process.  
          
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      • Liu Wujun
        Issue 2, Pages: 50-57(1988) DOI: 10.13756/j.gtxyj.1988.02.007
        摘要：This paper analyses the causes of coupling loss produced by self-focusing lens used in passive fiber components, solutions are proposed to such causes. The manufacturing process of fiber cord coupled with self-focusing lens by using optical alignment is presented, its application is described as well.  
          
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