最新刊期
卷 ， 期 6 ， 2010
- 摘要：We numerically analyze all-optical RZ to NRZ format conversion based on the Cross-Phase Modulation（XPM） in Highly Nonlinear Fiber（HNLF） and discuss the duty cycle of the RZ signals and the effects of the Q factor of fiber dispersion on the converted NRZ signals.Simulation results show that related higher Q factor can be obtained by carefully selecting the duty cycle of the input RZ signal and decreasing the dispersion difference between the RZ signal and continuous probe light.关键词：HNLF;format conversion;XPM;RZ code;NRZ code
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发布时间： - 摘要：With regard to the ONU Ethernet bridge subsystem with Dynamic Bandwidth Allocation（DBA） in GPON,the overall architecture of the network bridge subsystem in the ONU on-board Linux operating system is first analyzed and then a new algorithm for DBA in the network bridge is presented and evaluated.The experimental results show that the bridge with DBA can utilize the limited PON bandwidth resource of the GPON remote systems more effectively than common bridges.关键词：GPON ONU;network subsystem;network bridge;DBA
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发布时间： - 摘要：This paper presents a novel algorithm for implementing multicast and Differentiated Services（DiffServ） by edge routers in MPLS networks.This algorithm utilizes the Label Switched Paths（LSPs） between the edge routers at the branching nodes to transfer the multicast data packets and uses an information manager to calculate,manage and adjust the multicast tree and fulfills the QoS over the entire domain more effectively.Furthermore,this paper describes the specific details and the implementation principle of the algorithm and evaluates its feasibility and advantages.关键词：multicast;MPLS;DiffServ
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发布时间： - 摘要：H.248/Megaco messages can be encoded in both binary mode and text mode,but the latter mode is usually used in practical applications owing to its high readability.This paper finds out its layering features by investigating the text encoding norm and presents a layering parse architecture to decode the messages,in which the layering parse begins after the previous one is finished,increasing the parsing efficiency.This conclusion has some reference value for parsing protocol messages with similar encoding characteristics.关键词：H.248 protocol;text encoding;parse;layering
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发布时间： - 摘要：In view of the deficiencies of the wavelet threshold denoising method for vibration signals with non-uniform noise distribution,an algorithm based on Singular Value Decomposition（SVD） plus wavelet threshold denoising is presented.The matrix with the signal information and non-uniform noises is constructed by the rapture method,and the non-uniform noise is decomposed uniformly into several orthogonal subspaces by SVD.The rebuilt signal in the subspace with the maximal singular value is denoised by the wavelet threshold method.The results show that the proposed method is applicable in the vibration signal extraction under the non-uniform noise interference.Compared with the direct wavelet denoising method,the extracted signals are less distorted with more effective components.关键词：fiber grating;vibration;SVD;wavelet threshold denoising
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- 102
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发布时间： - 摘要：This paper analyzes the theoretical basis for the linear relationship between the Bit Error Rate（BER） in optical module sensitivity tests by extrapolation and sensitivity,which is verified in experiments.The test results indicate that the correlation coefficients of the sensitivities of 155 Mbit/s and 1.25 Gbit/s optical transceiver modules and lg [-lg（BER）] are 0.999 79 and 0.999 06 respectively,presenting a good linearity.Furthermore,it presents an optimized sensitivity measurement scheme by extrapolation method.关键词：BER;sensitivity;correlation coefficient;extrapolation method
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发布时间： - 摘要：This paper introduces the technologies and the northbound interfaces for Packet Transport Network（PTN） equipment,focusing on its technical characteristics,including its definition,network hierarchy,link frame format,service bearing and OAM/QoS technologies.In the light of its relevant technological characteristics,it designs the configuration management module for its northbound interfaces to facilitate the Network Management System（NMS） in its effective management and maintenance of the PTN equipment resources.关键词：PTN;T-MPLS;northbound interface;NMS;TMF
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发布时间： - 摘要：This paper introduces the NE cross configuration for Packet Transport Network（PTN） equipment and analyzes the need for its improvement.On the basis of several common PTN service features,it presents a service-driven NE cross configuration method.This method is faster and more accurate and can be used to reduce the probability of service mismatch due to user errors and improve the efficiency of service configuration.关键词：PTN service;NE cross configuration;service-driven
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发布时间： - 摘要：This paper presents a safe transition scheme,in which the core and converging equipment of the networks are updated to IPv6 step by step without affecting the normal applications of the existing IPv4 networks.Specifically,it goes through the following process: no equipment support,only core equipment support,part of converging equipment support and all converging equipment support,while investigating and implementing IPv4/IPv6 network intercommunication technologies,such as NAT-PT,IVI,BRT flyover crossing networks.关键词：safely;ALG;BRT
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发布时间： - 摘要：The mode field of photonic crystal fibers with regular hexagonal cladding air holes is analyzed by using RSoft.The characteristics of the Photonic Crystal Fiber Grating（PCFG） are computed and simulated by using the mode coupling theory and the transmission matrix method and the differences between the PCFG reflection spectrums with different cladding structures and fiber core sizes are compared.Simulation results show that diameter-to-pitch ratio and core sizes influence the resonance peak number and the resonant wavelengths.关键词：PCFG;reflection spectrum;mode coupling theory;transmission matrix method
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发布时间： - 摘要：In this paper,the ring resonator-based photonic crystal T-shaped channel-drop filter is investigated by the finite element method,in which the effects of the refractive index of the dielectric rods on the resonant frequency and normalized transmission are analyzed.On this basis,a filter model for the narrowband photonic crystal filter is designed.The numerical simulation results demonstrate the approximately linear dependence of the inner dielectric rods refractive index on the central wavelength of the drop waveguide output of the narrowband filter,which presents theoretical reference for the design and manufacture of photonic crystal filter.关键词：photonic crystal filter;ring resonator;finite element method;normalized transmission
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- 160
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发布时间： - 摘要：Aided by a Mach-Zehnder Interferometer（MZI） and Binary-Phase Sampled Fiber Bragg Gratings（BP-SFBG）,a multi-channel Optical Add/Drop Multiplexer（OADM） is constructed.A theoretical model for the OADM is first derived by using the transfer matrix method.Then the fast analysis and calculation of the BP-SFBG is performed by using the transfer matrix method and the Chebyshev identity.Finally,a simulated practical design is given and good numerical characteristics displayed,providing a useful reference for the development of specific devices.关键词：optical devices;OADM;BP-SFBG;MZI
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发布时间： - 摘要：In this paper,we simulate the reflective spectrum of the Sampled Fiber Bragg Grating（SFBG） by using the transfer matrix method and analyze the effects of the index modulation amplitude,duty cycle,sampling period and the length of grating on the reflective spectrum.On this basis,we use apodization function to eliminate the sidelobe disturbance and obtain a better reflective spectrum of an 8-channel SFBG.关键词：SFBG;transfer matrix;reflective spectrum;apodization function
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- 135
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发布时间： - 摘要：On the basis of the OPC technology,application software for a FBG-based temperature monitoring system is developed in the Visual C++6.0 programming environment.This software can preprocess the collected data,including denoising and jump signal removal,and demarcate temperature values via linear or non-linear calibrations,thus improving the monitoring accuracy of the system.Furthermore,it overcomes the defects resulted from the design of the FBG-based monitoring system with the conventional configuration software,conducive to the extensive applications of the FBG-based sensor system.关键词：FBG sensor;temperature monitoring system;GridCtrl;NTGraph.ocx;serial communication
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发布时间： - 摘要：This paper introduces a kind of Fiber Bragg Grating（FBG） pressure sensor.The FBG is bonded to the self-designed open-loop plexiglass to form a FBG sensor.The relation expression between the FBG wavelength shift and the pressure is given.The experimental results show that the sensor shows a good linearity in the range of measured pressure and the FBG pressure sensitivity coefficient reaches 0.162 nm /N,basically in agreement with the theoretical value.关键词：FBG;open loop;pressure sensor
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- 201
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发布时间： - 摘要：A transmissive intensity-modulation fibe-optic acceleration sensor is designed.A pigtailed collimator with a built-in Gradient-Index（GRIN） lens is directly used as a sensitive mass and two collimators are adopted for reception.The optical coupling efficiency of the light path is improved by addition and subtraction and ratio operation and the effects from light source disturbance and microbending loss are effectively compensated and the simulated computations and initial experimental data are given,which indicate that this acceleration sensor has good linearity,consistency and stability.关键词：fiber-optic sensor;acceleration sensor;intensity modulation;GRIN lens
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发布时间： - 摘要：In broadband communication systems,e.g.WCDMA,RF power amplifiers are subject to electric and thermal memory effects,resulting in spectral regrowth and adjacent channel interference,which cannot be cancelled by conventional memoryless predistortion technologies for the desired linearizing effects.For those memory power amplifiers,a novel memory polynomial predistortor is presented for those memory power amplifiers so as to track the variations of their characteristics and compensate the nonlinearity.关键词：memory effect;digital predistortion;memory polynomial;recursive least square
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发布时间： - 摘要：In order to solve the problem that the traditional Modulation and Coding Scheme（MCS） selecting rule improves the performance limitedly,this paper introduces a novel MCS selection criterion for the LTE system supporting an Adaptive-Modulation and Coding（AMC） scheme.The proposed criterion uses the sum of the weighted SNRs to determine the appropriate MCS for the AMC system.The simulation shows that when the throughput is 2.8 bit / symbol,the new rule brings the benefits of 2dB than the two-step rule,the proposed criterion applied to the AMC-LTE systems not only compensates for the channel variation over the slot duration to guarantee the required BER performance,but also maximizes the system throughput.关键词：Adaptive Modulation and Coding（AMC）;LTE;Modulation and Coding Scheme（MCS）;selection criterion
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发布时间： - 摘要：On the basis of the modeling of OFDM-ROF system,we obtain the expressions for such performance indexes as Spurious-Free Dynamic Range（SFDR） under external intensity modulation,analyze the effects of the average RF signal power on the OFDM-ROF system and compare it with the single-carrier ROF system.Results show that the average RF signal power should be reduced as much as possible in system design so as to achieve better performances.Under the same RF signal power,the SFDR of the OFDM-ROF system is about 5 dB lower than that of the single-carrier ROF system,so we should take measures in system design to reduce the Peak-to-Average Power Ratio（PAPR） of the OFDM-ROF system.关键词：OFDM;ROF;SFDR;PAPR
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发布时间： - 摘要：The asynchronous OCDMA system is a hot spot attracting much attention in recent years,but the study on the two-dimension code words appropriate for this system remains to be a blank.In this paper,the correlation of the Extended Quadratic Congruence（EQC） code in the system is analyzed and the method for constructing a two-dimensional time/frequency code for the system is given.The analysis of the autocorrelation and cross-correlation characteristics of the address code shows that the new code constructed with EQC and OOC has good autocorrelation and cross-correlation characteristics.关键词：asynchronous;OCDMA;EQC;OOC
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发布时间： - 摘要：This paper analyzes the basic characteristics of the civilian Pseudo-Random Sequence（PRS） codes in three bands of the Global Position System（GPS） signals,including generation configuration,modulating mode,message structure and signal energy.In connection with the features of L1 C/A code,it discusses the improvement of the civil PRS codes on GPS L2 and L5 signals,describes the differences and advantages of data and dataless channels and the functions of the Neumann-Hoffman（NH） code at L5 and qualitatively analyzes the effects of the new PRS code structure and modulation mode on the acquisition and anti-interference performances of the GPS signals.关键词：PRS;GPS;dataless channel;NH code
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发布时间： -
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