最新刊期
卷 ， 期 3 ， 2008
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- 摘要：In this paper,we introduce the background of Optical Burst Switching（OBS） generation,the principles and the system architecture of the OBS network and the structure of the edge nodes in the system.Adopting the computer simulation method with the tool of OPNET 8.1.A,we obtain the simulation results that when data packets of the edge nodes have a constant generation rate,the end-to-end delay is relatively fixed;while when the transmission rate of the edge node data packets suddenly increases,the end-to-end delay will have a certain fluctuations.关键词：optical burst switching;edge node;ETE delay;OPNET simulation
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发布时间： - 摘要：A novel RPR-based topological structure is proposed,which has fairly high survivability by using the vertical topology of ring networks.It makes full use of the advantages of the single ring data transmission mechanism of RPR and applies them to the macroscopical network architecture so as to enhance the bandwidth availability of the entire network.关键词：high survivability;bandwidth availability;vertical topology;logic node;logic ring net
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发布时间： - 摘要：A modified Parallel Interference Cancellation （PIC） technology is proposed to reduce the effect of multiple access interferences on the performance of the Optical Code Division Multiple Access（OCDMA） communication system.The expression of its Bit Error Rate（BER） is derived with OOC as the signature sequence code.The relationship between BER and the code length of OOC and between the code weight and the number of the active users are given according to the simulation and analysis.The results show that the system BER can be greatly reduced,the system performance improved and the minimal code length required for the system to satisfy BER≤10-9 is much shorter by using the modified PIC technology than by using the conventional PIC technology.关键词：OCDMA;multiple access interference;parallel interference cancellation
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发布时间： - 摘要：In the bipolar OCDMA system,bipolar codes with better correlation properties are used in the conventional unipolar OCDMA channels in light of the unipolar-bipolar code transformation.A bipolar complete complementary sequence-based OCDMA system coding/decoding method and system model are proposed.The simulation results show that it has much better system properties than the Gold sequence-based OCDMA system and that using complete complementary sequences as the address codes,the MAI in the OCDMA system can be effectively reduced and the communication quality improved.关键词：OCDMA;bipolar code;unipolar code;complete complementary code;correlation property
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发布时间： - 摘要：This paper studies a specific Radio-Frequencyover-Fiber scheme for WiMAX（Worldwide Interoperability for Microwave Access）based broadband wireless access systems.This scheme describes the structure of the downlink between the center station and the base stations.Theoretical ratiocinations and performance analyses are conducted in terms of power budget and carrier bandwidth selection.The results are helpful for the design of practical systems in these respects.关键词：radio frequency-over-fiber;power budget;WiMAX;carrier bandwidth
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发布时间： -
Comparison of error-correcting code performance in wireless optical communication simulative systems
摘要：In view of the severe attenuation of optical signals in atmospheric channels,we propose a simulation model for Turbo code system constructed by using Simulink and compare its BER performance with those of the simulation systems without using the channel coding scheme and with the convolutional coding scheme.The results demonstrate the superiorities of Turbo code in wireless optical transmissions in terms of low BER and provide a theoretical basis for its applications in these systems.关键词：wireless optical communication;Turbo code;convolutional code;Matlab simulation- 2
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发布时间： - 摘要：This article proposes a quantification model for the security risks of dendriform chart-based electric power optical fiber communications networks and analyzes in detail the relationship between the risks and its essential factors: assets,threat,vulnerability and the countermeasures. In addition,it specifically explains by using a formula how these risks are constituted,elaborates on the concept classification of each factor in line with the electric power communications networks,obtains their corresponding relationship by establishing a dendriform chart model,reasonably evaluates them,thus obtaining the risk value through computations,and finally verifies the model through practical cases.关键词：electric power optical fiber communication network;risk factor;dendriform chart model
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发布时间： - 摘要：A novel Photonic Crystal Fiber（PCF） is designed,in which a small air hole is introduced in its core to form a defect and the diameter of the first ring of air holes is changed.Its dispersion properties are studied by adopting the plane wave method,which shows that it has lower and flatter dispersion curve than the traditional PCF.By optimizing its structural parameters,a PCF with near zero and flat dispersion in the wavelength range of 1 350～2 010 nm can be designed.Its dispersion variation ΔD<0.5 ps/（km·nm） and dispersion slope variation ΔDslope<0.02 ps/（km·nm2） in the wavelength range of 1 3202 040 nm.关键词：PCF;flat dispersion;dispersion slope;plane wave method
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发布时间： - 摘要：The effects of the structural parameters of the planer photonic crystal on the characteristics of its forbidden band and defect mode have been studied by using the Finite-Difference Time-Domain（FDTD） method.After defects are introduced in the air hole structure,the dielectric band frequency will move upwaaard with the increase of the radius of the acceptor defect air hole,while the air band frequency will move downward with the decrease of the radius of the donor defect air hole.关键词：planer photonic crystal;defect mode;FDTD method;Q factor
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发布时间： - 摘要：The paper analyzes the Four Wave Mixing（FWM） phenomenon of distributed raman fiber amplifier on Leaf.We observed the FWM phenomenon in broadband distributed Raman fiber amplifier（DRFA）.This is one of the nonlinear effects which limits the performance of Raman amplified systems.We analyze the FWM effects for different fiber types.Finally we reduced the FWM influence successfully by choosing proper wavelengths in experiment.关键词：DRFA;FWM;ASE
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发布时间： - 摘要：In this article,the merits of Mach-Zehnder external modulator for fiber-optic communications are first introduced and the importance of controlling the optimal bias point of M-Z external modulator explained.Then,its transfer function and curve are theoretically analyzed and the characteristics and control mechanism of the optimal bias point deduced.Finally, the control technique and realization of the optimal bias point are proposed and varified.关键词：fiber-optic communication;M-Z external modulator;bias point;dither signal;automatic control
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发布时间： - 摘要：The Optical Line Protection（OLP） system based on selective transceiver optical switch is suitable for various optical transmission systems,such as SDH and DWDM systems,effectively enhancing the survivability of the entire optical network.Using modularized hardware configuration and mature telecom network management architecture,the OLP system implements the protection,restoration,status monitoring and route scheduling of the optical lines in optical transmission systems,improving the system reliability and stability.关键词：OLP;optical line monitoring;selective transceiver optical switch;network management system
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发布时间： - 摘要：The paper analyzes the reason why 1 060 nm waveband radiation is caused in Er/Yb co-doped double-clad Optical Fiber Amplifiers（OFA）and investigates in the spectrum characteristics of this radiation by means of forward and backward pump.Comparing with the Yb doped OFA,it explains the function of Er-doped ion absorption,i.e.the output spectrum wavelength is caused to drift towards the long-wavelength side.When the pump power is increased,1 060 nm waveband radiation power will rise accordingly,which should be restrained to avoid self-excitation.关键词：OFA;double-clad fiber;Er/Yb co-doped
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发布时间： - 摘要：Error analysis for polarization controllers with high accuracy is necessary as they are very important in high-rate optical fiber communication systems,coherent optical fiber communication systems and fiber-optic sensor systems.In this paper,error analysis is performed on the wavelength correlativity of HQQ-type polarization controller and the changes of the azimuth angle and ellipticity angle of the output polarization state with the wavelength are observed by simulation.This result is very important for the error compensation of the controller.关键词：polarization controller;waveplate;error analysis
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发布时间： - 摘要：In this paper,a single PIN detector integrated optical WDM that is mainly used in fiber-optic CATA is analyzed and tested.This device is used for reception of the up/down stream of data and the reception of CATV signals.The test results show that the test indexes can satisfy the conditions of responsivity of >0.9 A/W in 1 550 nm,insertion loss of <0.8 dB,isolation degree of >20 dB in 1 550 nm,return loss of >45 dB,CSO of >70 dB,and operating temperature of-40～85℃.关键词：WDM;integration;analog PIN
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发布时间： - 摘要：A novel electro-optic polymer optical switch with Attenuated Total Reflection（ATR） configuration is proposed,which is used to electrically control the coupling efficiency of the incident light in the ATR configuration into the guided modes by using the electro-optic effect of the polymer.This device is characteristic of small power consumption,large extinction ratio,fast response speed,good stability,simple manufacturing processes and low cost.关键词：optical switch;polymer;electro-optic effect
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- 114
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发布时间： - 摘要：A Differential Evolution（DE） algorithm is used to reconstruct the parameters of a uniform Fiber Bragg Grating（FBG） from the target reflection spectrum.Using the DE algorithm,a set of parameters,i.e.the fiber grating parameters for the reconstruction,are found,with which the calculated reflection spectrum shows the smallest deviation from the target spectrum.Numerical examples demonstrate that this is a highly efficient and accurate parameter reconstruction approach.关键词：FBG;differential evolution algorithm;parameter reconstruction
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发布时间： - 摘要：This paper first introduces the principle of the interworking between intelligent networks and the internet,the fundamental concept of PSTN-Internet Interworking（PINT） services and the network architecture,and analyzes the PINT protocol.Then,it presents the model of the interworking and describes its practical realization in connection with the click to dial services.Finally,it discusses the security issues in interworking.关键词：PINT services;network interworking;click to dial;PINT protocol;security
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发布时间： - 摘要：Consisting of the basic protocol and the extended application protocol,Diameter protocol is used as an AAA protocol in IP Multimedia Subsystems（IMS）.This paper focuses on the analysis of the SIP application and credit control application of extended Diameter protocols in IMS,with the emphasis on their applications in authentication,authorization and online billing.关键词：IMS;Diameter protocol;AAA
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发布时间： - 摘要：In this article,ADPCM-based study and design of synthetic voice chips are completed.The voice signals of the compressed ADPCM format are first decoded and then the decoded signals are translated into a Pulse Width Modulation（PWM） wave,directly driving the speaker to produce sounds. Compared with the traditional way of synthetic voice output by using weight current D/A conversion,the proposed approach has such advantages as small power consumption,stronger technological adaptability and stable and reliable design.关键词：ADPCM;D/A conversion;PWM;synthetic voice
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发布时间： - 摘要：This article discusses the Step-by-step decoding algorithm for the RS code in the digital communication system,gives its the basic principle and realizes the RS（7,3） code on FPGA,and the actual simulation effect chart.The result indicates that the designed electric circuit can correct any two errors in 7 received marks.As the solution of erroneous localization multinomial by using this algorithm,the decoding process can be simplified and decoding speed increased,facilitating the realization of large-scale programmable components.关键词：Step-by-step decoding;FPGA;digital communication system
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发布时间： - 摘要：High-rate UWB-PPM signal transfer is a key technology for indoor UWB communications.On account of the characteristics of binary UWB PPM signals,quick synchronization of the pulse energy captured by using multiple parallel integrators is achieved and RF sync detection of PPM completed.System transfer tests and simulation show that this detection method has good anti-ISI performance in indoor multi-path channels.关键词：UWB;PPM;parallel capture;RF synchronization detection
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发布时间： - 摘要：Single threshold denoising based on wavelet transform is effective in certain cases as fixed models are used for threshold estimation,but it is often unsatisfactory in some specific projects.This paper presents a wavelet transform-based mixed threshold denoising method,in which weight coefficients are added to different thresholds and fairly ideal threshold are obtained by optimizing the weight for the object function.The simulation results show that compared with the conventional methods,this method better in denoising effect and maintains the detailed features.关键词：wavelet transform;mixed threshold;denoise
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