基于FPGA的高速光纤传输系统物理层研究

对一种基于FPGA(Field Programmable Gate Array)的高速光纤传输系统物理层进行了研究。该系统使用Altera公司的Arria II GX系列芯片,通过对FPGA高速数据收发器模块及相关控制逻辑的例化和设计,实现了低速并行数据的高速串行化,并使用小型SFP(Small Form Factor Pluggable)光模块对串行数据进行光电转换,通过光纤进行传输通信。实际测试验证了设计的正确性,可实现与更高层协议的灵活对接,有较高的实用价值。     

基于旋转光纤连接器的高速红外图像传输技术

提出了一种基于光纤旋转连接器,从连续旋转扫描的探测器头部向机下传输高速红外图像的方法,并讨论了其中的关键模块的设计原理及方法.实际应用结果表明,系统稳定可靠,速度、稳定性和误码率性能与采取传统的接触式电滑环的系统相比有很大提高.     

单根多模光纤数字扫描成像方法

针对现有多模光纤数字扫描成像方法,形成扫描聚焦光斑计算量大、速度慢的问题,提出了一种基于自适应并行坐标（Adaptive Parallel Coordinate,APC）算法的单根多模光纤数字扫描成像方法,通过控制多模光纤输入端的光场,在单根多模光纤出射端实现光斑的聚焦和扫描。建立了单根多模光纤数字扫描成像数学模型;采用自适应并行坐标算法对空间光调制器（Spatial Light Modulator,SLM）加载相位进行优化,有效缩短了扫描聚焦光斑的形成时间,提高了成像速度。实际生成3030个聚焦光斑,对50 m50 m范围的分辨率板进行扫描成像。实验证明,该方法实现了单根多模光纤对距离光纤端面60 m处平面内的目标成像,分辨率达到2.46 m。     

复杂调制进入光纤

对更庞大数据流量的需求似乎永无止境,并且其加速度远超出很多人的预期,因而造成了光纤网络上的瓶颁.     

光纤传输技术在雷达信号记录重演系统中的应用

介绍基于StratixGX系列FPGA的光纤传输技术在雷达信号记录重演系统中的应用。文中分析了光纤传输的优点以及技术实现的可能性,着重阐述了光纤传输系统的结构组成及具体应用,并给出了主要芯片的型号。经验证,该光纤传输技术性能稳定。     

磁共振成像MRI的原理及其发展动向

综述MRI的原理及其发展动向.     

数据采集卡光纤高速收发模块的设计

设计了一种基于光纤通道协议的数据持续传输方案.在光纤通道帧和信令协议的基础上,利用Stratix IV GX系列FPGA实现了成帧、8B/10B编码等功能,设计了光纤通道协议的FC-1和FC-2层.利用FPGA内部的高速收发器IP core完成了并行数据向高速串行数据的转换.最终实现了数据的高速持续传输,并对整个系统的...     

通信工程中光纤传输技术的发展

时代在快速发展,对光纤通讯技术的运用,已经成为现代社会逐渐发展的技术之一.光纤技术在运用的时候,不仅具有比较优秀的传输速度,在传输信息的过程中,整个传输过程比较稳定,给整个社会的发展带来了多方面的信息传输渠道.本文主要针对通信工程中光纤传输技术在之后的发展进行分析,首先对光纤技术进行了解,深入分析新技术在现代社会的应用...     

数字光纤直放站中CPRI协议的FPGA实现

为了实现对特定地区的低成本覆盖,将无线基站的控制部分和射频部分分离.介绍了公共通用无线接口(CPRI)协议的规范,给出了基于LATTICE半导体公司的LFE2M35E的FPGA实现方案.采用硬件描述语言Verilog HDL设计各个功能模块.软件平台是LATTICE半导体公司提供的IspLEVER Project Na...     

Multi-dimensional adaptive transmission technique for shortto-medium reach optical fiber communication system

According to the features of short-to-medium reach optical fiber communication systems,three high performance adaptive modulation and coding schemes were investigated.In the first one,a new dimension,forward error correction (FEC),was introduced to the traditional bit and power loading (BPL) scheme,and the three-dimensional adaptive modulation and coding were achieved.The modulation format and FEC code were allocated based on look-up table (LUT).The proposed algorithm has lower complexity and higher data rate compared to the BPL scheme.The second one was also based on LUT method where one similar data rate with the BPL scheme was achieved using partitioned precoding,but peak-to-average power ratio was reduced up to two dB,and the power efficiency was improved.In the last scheme,probabilistic shaping QAM was adopted as the modulation format,and shaping gain and almost indefinitely fine modulation granularity were achieved at the expense of certain complexity.With adaptive partitioned precoding,without decreasing data rate the number of PS-QAM was limited to reduce the complexity.The experimental results demonstrate that the proposed scheme outperforms the BPL scheme in terms of data rate and receiver sensitivity.     

雷达数字信号光纤传输系统发射模块的设计

介绍了一种采用FPGA技术实现的雷达数字信号光纤传输系统。根据雷达信号的特点，采用特殊的帧结构形式，在一根光纤上实现了雷达多路数据的传输。     

光纤传输用的磁光隔离器

本文报导了光纤通信用光隔离器的研究工作.隔离器由稀土铁石榴石法拉第旋转器及两只方解石棱镜组成.在波长为1.15微米时,器件插入损耗为2.4分贝,隔离比为34.8分贝.讨论了使用不同的复合稀土铁石榴石材料及采用不依赖偏振光技术对器件性能的改进.     

Coherent optical fiber transmission

Essential technologies for developing coherent optical fiber transmission systems are reviewed from the viewpoint of regenerative repeater spacing and transmission data rate improvements. After describing the system features behind these advantages, recent progress in individual device and system technologies is delineated. Such progress includes frequency stabilization and linewidth reduction of semiconductor lasers, optical phase or frequency modulation, AM and FM noise suppression in coherent receivers, optical polarization stabilization and control in signal transmission, and optical direct amplification. Also described is progress in coherent optical transmission experiments carried out in many laboratories. Finally, future problems are discussed on the basis of the current state of the art.     

A low-pass digital optical filter for optical fiber communications

A passive, all-optical fiber device that limits the rate at which digital information can be transmitted over a single-node fiber is described. Experimental results that demonstrate the frequency response of the device and its effect on baseband intensity-modulated digital transmission are presented. A variety of issues related to the performance of these devices is discussed     

New transmission code for digital optical communications

A new code with the aim of facilitating realisation of a simple repeater is presented and compared to the other codes with similar properties. Its spectrum is calculated and a simple coder and decoder are proposea.     

光纤通信系统中的非线性数字补偿调制研究

为了分析不同调制方式下的光纤通信系统非线性数字补偿效果,文中以具有标准单模光纤(SSMF)传输链路的间隔波分复用(WDM)光纤通信系统为基础,通过建立信号之间、信号与噪声之间相互作用引起的非线性失真数学模型,利用互信息(MI)与可达信息速率(AIR)作为多信道数字反向传播(MC-DBP)计算复杂度指标,研究了理想Nyquist间隔光纤通信系统中调制方式与MC-DBP性能的关系。实验结果表明,最大信道DBP系统的非线性失真与调制方式无关,而电子色散补偿(EDC)和部分信道DBP的非线性失真取决于调制方式。     

New preprocessing technique for digital facsimile transmission

A new preprocessing technique which removes unwanted notches and random noise generated by electronic scanners is presented. Using a 3 element by 3 element mask, the central picture element is altered from black to white, or vice versa, if the surrounding elements correspond to a predetermined pattern. A significant improvement in both subjective image quality and coding efficiency is observed.     

Research on optical fiber magnetic field sensors based on multi-mode fiber and spherical structure

A magnetic field sensor with a magnetic fluid (MF)-coated intermodal interferometer is proposed and experimentally demonstrated. The interferometer is formed by sandwiching a segment of single mode fiber (SMF) between a segment of multi-mode fiber (MMF) and a spherical structure. It can be considered as a cascade of the traditional SMF-MMF-SMF structure and MMF-SMF-sphere structure. The transmission spectral characteristics change with the variation of applied magnetic field. The experimental results exhibit that the magnetic field sensitivities for wavelength and transmission loss are 0.047 nm/mT and 0.215 dB/mT for the interference dip around 1 535.36 nm. For the interference dip around 1548.41nm, the sensitivities are 0.077 nm/mT and 0.243 dB/mT. Simultaneous measurement can be realized according to the different spectral responses.     

A technique for accurate magnetic resonance imaging in the presence of field inhomogeneities

A technique for producing geometrically accurate magnetic resonance images (MRIs) with undistorted intensity in the face of high levels of static field inhomogeneity arising from either source is presented. The technique requires the acquisition of two images of the same object with altered gradients. On the basis of a knowledge of these gradients it employs an automatic postprocessing step that exploits some invariant characteristics of the distortions to produce a rectified image from the two acquired images. No phantom imaging is involved and no operator interaction is required. The technique is theoretically justified and compared to other techniques, and experimental results that show that the technique works are presented. The improved accuracy in geometry and intensity may improve reliability of stereotactic surgery, may enhance the feasibility of both clinical and industrial imaging via external fields, and may increase the resolution of microscopic imaging.