最新刊期
      卷 ， 期 4 ， 1996
      • Mei Suohai\ Liu Wen\ Hu Meizhi
        Issue 4, (1996)
        摘要：This paper discribes the principle, design and performance of the voltage controlled oscillators at 155.52 MHz, 622.08 MHz and 1 244.16 MHz using surface acoustic wave（SAW） and surface transverse wave（STW） devices. By using low loss, high Q SAW delay lines or STW resonators and highly efficient tuned amplifier circuits, oscillators have very low noise （ better than -140 dBc/Hz at 100 kHz offset from carrier ）, provide a high output power （ >9 dBm ）, low temperature frequency variations and a tuning range of more than 400 ppm.  
        关键词：oscillator;SAW;STW;microwave frequency source   
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      • Yu Jianjun\ Zhang Xiaoguang\ Yang Qimin et al.
        Issue 4, (1996)
        摘要：Gbit/s,23 km optical soliton transmission was achieved using normal dispersion fiber elimination chirp.The fundamental and high order optical Soliton were observed.A new phenomena was found.The spectral feature of the positive chirp pulse transmission along normal dispersion fiber was changed.  
        关键词：soliton transmission;EDFA;normal dispersion fiber   
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      • Yang Guomin\ Wang Baotai
        Issue 4, (1996)
        摘要：This article introduces the principle and development of 622.08Mbit/s SDH equipment CID immunity measurement instrument,analyzes the creating method and initial phase of pseudo random binary sequence and the alignment method of reciver circuit,gives the result of circuit simulation and experiment.  
        关键词：SDH;CID;SDH measurment   
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      • Wang Aiguo\ Xiao Dingzhong
        Issue 4, (1996)
        摘要：n improved BP neural network, that is mutilayer double link artificial neural network whose nodes have the abilities of study, is proposed, and a correspondent algorithm is given. For examples of XOR problem and symmetry test, a functional comparison is made between the improved algorithm and the conventio nal algorithm. A primitive test of isolated word speech recognition based on the improved BP neural network is made in this paper.  
        关键词：BP neural network;speech recognition;neural unit   
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      • Qiu Wenrong\ \ Shi Sheping\ \ Gu Wanyi
        Issue 4, (1996)
        摘要：This paper describes a multichannel FM Subcarrier Multiplexed（SCM） lightwave system we devloped.The noise characteristics of SCM lighwave system are also discussed.This equipment can be used as multichannel CATV optical transmission system.We use an F P cavity LD and a PIN FET receiver,and gets a performance of SNR>55dB with received TV video signals.  
        关键词：FM SCM;optical fiber analog communication;optical fiber CATV   
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      • Wang Jun Jun
        Issue 4, (1996)
        摘要：This paper introduces the application of SDH in the access network and subscriber loop, compares the features and advantages/disadvantages between SDH and traditional PDH, and describes the SDH network configuration and equipment application, analyses and describes the strategies and approaches of SDH evolution in the access network, including the evolution of network management. Finally, some examples of SDH application in the access network are given, including NTT’s SDH local area service node and UK’s integrated CATV/SDH network.  
        关键词：fiber access network;SDH;subscriber loop;CATV   
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      • Liu Xianbing\ Zou Linsen
        Issue 4, (1996)
        摘要：Four numerical methods are employed to compute the chromatic dispersion characteristics of optical fibers.They are the method of solving transcendental algebraic equations,the matrix perturbation method,the Galerkin method and the finite difference method.All of these methods can compute the chromatic dispersion characteristics of optical fibers fastly and accurately  
        关键词：chromatic dispersion;numerical computing;optical fiber   
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      • Zhu\ Yinian
        Issue 4, (1996)
        摘要：The generalized Gaussian formalism is applied to praseodymium fluoride fiber amplifiers to obtain accurate analytic expressions for portion of the core is investigated.It is found that dopant confinement improves the efficiency of these fiber amplifibers.The optimum cutoff wavelength for fibers with confined dopant is longer than that for fibers with fully doped cores.  
        关键词：dopant distribution;Pr doped optical fiber amplifier;dopant confinement   
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      • Pang Yong\ Jiang Peixuan\ Xu Daxiong
        Issue 4, (1996)
        摘要：In theis paper,dual port all fiber reflectors using two stage directional couplers were proposed,the reflectivity and transmissivity of both optical field and intensity were derived,respectively,and the characteristics were analyzed.  
        关键词：optical fiber communication;directional coupler;fiber reflector   
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      • Du Hui\ Song Xianzeng
        Issue 4, (1996)
        摘要：Jitter and wander performance is an important parameter in opticle communication equipments.This article synthesises and analyzes the jitter and wander performence in SDH network,and also gives some discussions about applicable measurement principles and methods.  
        关键词：jitter and wnder;mapping;jitter transfer function   
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      • Fong Peizhen
        Issue 4, (1996)
        摘要：The basic traffic control technology connection acquisition control （CAC）,usage parameter control （UPC）,priority control,congestion control, etc are introduced and analyzed.  
        关键词：traffic control;CAC;UPC;priority control;congestion control   
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      • Issue 4, (1996)
        摘要：ＩＴＵ－Ｔ第１３工作组１９９６年会议（Ｑ２１／ＷＰ４／ＳＧ１３）漆启年（邮电部武汉邮电科学研究院）ＩＴＵ┐ＴＳＧ┐１３Ｍｅｔｉｎｇｉｎ１９９６（Ｑ２１／ＷＰ４／ＳＧ１３）ＱｉＱｉｎａｎ１概况Ｑ２１／ＷＰ４／ＳＧ１３研究子课题涉及的建议有：关于术语的建...  
          
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      • Issue 4, (1996)
        摘要：武汉邮科院一批“八五”科技攻关成果和个人受到国家表彰于１９９６年１１月１２日在北京人民大会堂召开的“八五”国家科技攻关总结表彰大会对国家“八五”攻关重大科技成果和作出优异成绩的个人给予表彰。邮电部共有９人、１０个项目获得表彰。武汉邮科院４项“八五”攻...  
          
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