最新刊期
卷 ， 期 6 ， 2008
- 摘要：As far as 10 Gbit/s systems are concerned,intersymbol interferences brought about by nonlinear effects must be removed in long-haul transmissions.At present,the dispersion compensation,EDFA and Raman technologies are often applied for this purpose.In-depth researches on these technologies have greatly improved the line transmission quality and extended the repeaterless line transmission span.This paper introduces a method for improving the system OSNR and extending the transmission span by enhancing the input power of the EA laser.Experiments prove that optical input power at 18 dB can still ensure the transmission quality.关键词：single-channel system;repeaterless transmission;nonlinear effect
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- 55
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发布时间： - 摘要：In view of the traffic grooming issues in WDM networks,the Relative Capacity Influence（RCI） algorithm is used to deal with such issues as Routing,Wavelength and Time-slot Assignment（RWTA） in WDM networks on the basis of a trunk-switched network model.By using this algorithm,the wavelength and time slot assignment issues that are usually dealt with separately can be solved simultaneously.The simulation results prove that the algorithm performs better than the existing ones when these issues are dealt with separately.关键词：WDM network;RWTA;trunk-switched;RCI
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- 109
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发布时间： - 摘要：The Optical Burst Switching（OBS） network is a typical representative of the next generation IP over WDM networks.In this paper,the performance analysis is made of the multi-priority traffic contentions in the optical buffer-equipped core node in OBS networks.The packet loss probabilities and average waiting latency for different priority traffics are given.The results provide theoretical references for the realization of OBS networks.关键词：OBS;contention;optical buffer;packet loss probability;latency
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- 51
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发布时间： - 摘要：This article presents a Multi-QoS Constrained（MQCTR） T-MPLS recovery algorithm on the basis of the analysis of the limitations of the traditional algorithms.In order to enhance the success rate of recovery path set-up,it sets forth a multi-QoS-threshold constrained routing mechanism in line with the constrained routing idea.Finally,it applies,as an example,this algorithm in a mesh network and performs simulation and analysis of its performances.The results show that this algorithm does not only supports multiple recovery modes,but also has multiple service differentiation functions,which is of major significance to enhancing the survivability and robustness of carrier-level T-MPLS networks.关键词：T-MPLS;survivability;fault recovery;constrained routing
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- 51
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发布时间： - 摘要：Pulse broadening caused by dispersion in single mode fibers is studied by the non-linear Schrodinger equation and Principal State of Polarization（PSP） model.Rational estimation of the chromatic dispersion and Polarization Mode Dispersion（PMD） in optical communication systems is made by detailed calculations and the effects of dispersion tolerance on the system transmission analyzed.The results presented in this paper are significant to practical system design.关键词：fiber-optic communication;chromatic dispersion;PMD;dispersion tolerance
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- 256
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发布时间： - 摘要：The paper proposes a general design scheme for the integrated access terminals in FTTH.In this scheme,voice,video and data services are converged on the basis of PAS6301 chips on the user side.Especially,in terms of video services,combining the advantages of IPTV and DVB,the system provides a platform for receiving these two kinds of signals to the users,who can use the ordinary TV sets to receive both the digital TV programs encoded by MPEG-2 and the IPTV programs encoded by H.264.关键词：FTTH;EPON;DVB;IPTV;VoIP
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- 78
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发布时间： - 摘要：A Cyclic Redundancy Check（CRC） 32 generator is implemented in C++,which can be used to generate the exclusive OR expressions of each CRC32 bit simultaneously.Verifications in FPGA with the help of Verilog HDL show that the generated exclusive OR expressions are suitable for parallel calculations of CRC32 in high speed data transmission systems.关键词：parallel calculation;CRC;FPGA;Verilog HDL
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- 119
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发布时间： - 摘要：The generation of the Optical Orthogonal Code（OOC） with good performances is one of the key techniques for OCDMA communication.A modified method for the generation of（n,w,1,1） OCC（denoted by GA-OOC） with arbitrary code length and code weight by using the genetic algorithm is presented.A new code matrix is designed and new immigrants added in iteration.The simulation results indicate that the modified algorithm converges faster,the GA-OOC-based OCDMA system uses its hardware resources more effectively and has a lower BER as the code length and the code weight are independent from each other.关键词：fiber-optic communication technology;OCDMA;OOC;BER
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- 104
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发布时间： - 摘要：This article first introduces the fundamental principles of dispersion compensation.Then it explains the latest dispersion compensation technologies at home and abroad,including the Dispersion Compensation Fiber（DCF） that is technologically matured and commercially applied in large scales and Fiber Bragg Grating（FBG） that is constantly technologically maturing,and describes the hotspots in the future dispersion compensation researches: Photonic Crystal Fiber（PCF） dispersion compensation and electronic dispersion compensation.Finally,it points out the orientation of the development of dispersion compensation.关键词：dispersion compensation;DCF;FBG;PCF
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- 921
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发布时间： - 摘要：In this paper,DSP-based logic control module software design for Polarization Mode Dispersion（PMD） compensation systems is implemented by software programming and debugging.The system workflow,software and hardware frame and the applications of PSO algorithm module in DSP systems are introduced in detail.Finally,the application of DSP system in the 2nd-order PMD adaptive compensation systems is verified,the result of which shows that the DSP logic control module produces a great compensations effect on the 1st-and 2nd-order PMD.关键词：PMD;logic control module;software design
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- 66
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发布时间： - 摘要：The coincidence characteristics of the self-imaging multimode interferences of two-dimensional triangle photonic crystal waveguides are investigated by simulation and computation.A two-dimensional photonic crystal 1×2 splitter is proposed.On the basis of self-imaging interference effects,its characteristics are calculated and analyzed by finite-difference time-domain method.Investigations show that the transmissivity of this splitter can be as high as 96% because of the self-imaging effects in the multimode interference region,which can find major potential applications in photonic crystal optical integrated circuits.关键词：photonic crystals waveguide;self-imaging effect;multimode interference
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- 217
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发布时间： - 摘要：Fiber Bragg Grating（FBG） flowmeter is a new type of flowmeter based on optical signals.Its wavelength,phase and other parameters are all changed when its fiber and grating are subject to the actions of fluids.The external flow variations can be measured by measuring the optical signal changes.The operating principles of several types FBG flowmeters are described,their merits and demerits analyzed,and the prospects of their development are summarized.关键词：Fiber Bragg Grating（FBG）;flow measurement;sensor
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- 405
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发布时间： - 摘要：The Wavelength-Selective Switch（WSS） is a subsystem of the Reconfigurable Optical Add/Drop Multiplexer（ROADM） that is rapidly developing in recent years.It can switch over between any input and output ports,greatly enhancing the networking capability of DWDM equipment.This paper briefly describes the features of several technologies for the realization of WSS,illustrates the structure of the LC-based WSS,presents the specific optical circuit design scheme for the 1×2 WSS,and theoretically analyzes the feasibility of its structure with the help of Jones matrix.关键词：ROADM;WSS;LC technology;Jones matrix
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- 217
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发布时间： - 摘要：The arbitrary channel space of two kinds of fibers and the steady-state analytical results of the unidirectional Stimulated Raman Scattering（SRS） of N-channels are given by using the photon transfer theory and a novel gain-flattened broadband Fiber Raman Amplifier（FRA） presented.The 64-channel WDM system is simulated and a new method for the gain flattening of FRA provided.关键词：FRA;silica fiber;gain flattening
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- 168
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- 5
发布时间： - 摘要：A database transplantation method is presented by virtual Open DataBase Connectivity（ODBC） function.In other words,making use of the similarity between ODBC and the Oracle Call Interface（OCI） of Oracle access database modes,the existing ODBC function is rewritten by using the OCI function,while keeping the ODBC interface function constant.It is proved in practice that this database transplantation method is modified slightly,but the data accessing speed is faster.关键词：service data function;OCI;ODBC;handle
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- 27
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发布时间： - 摘要：In this paper,two common schemes,Digital Signal Processing（DSP） and Field Programmable Gate Array（FPGA）,for the implementation of signal acquisition and spectrum display in embedded systems are discussed and their: advantages and disadvantages summarized and analyzed.A detailed introduction is given to the implementation of a specific FPGA.Modular design is adopted for the system and all the functional modules described in Verilog HDL,having independent IPR.Comprehensive simulation results indicate that the system satisfies the requirements for high-speed signal acquisition and spectrum display.关键词：DSP;FPGA;FFT;VGA
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- 128
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- 1
发布时间： - 摘要：In the IPTV system,Set-Top Box（STB） is a very important unit,which decides to a certain extent the growth of IPTV.This paper proposes a design scheme on the basis of SIGMA DESIGNS EM8622L chips and the Linux operating system,including the system design,hardware design and software design.The IPTV set-top box designed on the basis of this scheme has basic service functions and extended service functions.关键词：IPTV;STB;Linux operating system;hardware design;software design
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- 147
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- 14
发布时间： - 摘要：This paper studies the development of the Radio Frequency Identification（RFID） handset by using the RFID reader module and a PDA.It first gives a brief description of the hardware,the software development flow and the functional modules of the RFID checkpoint system.Then,it studies such key issues as communication interfaces and database synchronization in the course of the development.Finally,it makes a comparison between the newly developed RFID handset and the conventional ones.The results show that the former is characteristic of convenience,fastness and direct vision and improves work efficiency in applications.关键词：PDA;RFID;WinCE;communication interface
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- 239
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发布时间： - 摘要：A method for the design of the broadband power amplifier by small signal approach is introduced when large signal models of devices can not be acquired.The small signal approach is adopted to perform the design,optimization and simulation of the electric circuits simultaneously according to the indexes of the amplifier by using ADS software on the basis of GaAs FET so as to implement the broadband power amplifier design with the expected values.关键词：broadband power amplifier;ADS software;S-parameter;gain
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- 501
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发布时间： - 摘要：Using finite element method,this paper investigates the influences of two deformed symmetrical double ridged,（elliptical and circular）,waveguides on their transmission characteristics.It calculates the cutoff wavelength and single-mode bandwidth at the change of the ridge dimensions,gives the dominant mode field pattern and the corresponding curve of the deformation vs.the effects on the cutoff wavelength and single mode bandwidth and analyzes the transmission characteristics with the changes of the waveguide dimensions.These studies provide valuable references for the applications and study of the deformed double-ridge waveguide.关键词：finite element method;cutoff wavelength;single-mode bandwidth;dominant mode field pattern
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- 131
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发布时间： - 摘要：On the basis of the Long Term Evolution（LTE） tail-biting convolutional code,this paper introduces the Circular Viterbi Algorithm（CVA） and the Wrap-Around Viterbi Algorithm（WAVA） for this code.Combining their advantages,it makes improvement on the existing algorithms and reduces the decoding computational complexity.The simulation results show that compared with WAVA,the improved algorithm has better performances and reduces the computational amount by 1/4.关键词：LTE;tail-biting convolutional code;CVA;WAVA
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