光纤-英文简介
Optical fibers and their application
李慕姚1351626 The optical fiber is short for an optical waveguide fiber, and is a light transmission tool adopting the principle of total reflection of light in fibers made of glass orplastics. The inside part of optical fibers called core,it is usually made of glasswhich has high refractive index.And the diameter of multimode fiber core is 50um or 62.5um. The outer layer called coating, which is made of resin to protect the inside layers. And the part between the core and coating called caldding, whose diameter isusually 125 um.
The operation of fiber lasersis based on the principle of total internal reflection. When the light is transmitted in the core,the angle of the incident light is greater than the critical angle of total reflection,Light can not through the interface and will be reflected back.
The classification of the optical fiber is mainly from the working wavelength, the refractive index distribution, the transmission mode, the raw material and the manufacturing method. According to the working wavelength, it can be divided into UV fiber, considerable fiber, fiber optic near infrared and infrared optical fiber.According to the transmission mode, it can be divided into Single-mode fiber and multimode fiber.Etc.
Optical fiber transmission has many outstanding advantages such as wide bandwidth, low loss, light weight, strong anti-interference ability, reliable performance.So it used in a lot of field. First of all,optical fiber can be used in optical fiber communication technology incommunications technology.Optical communication system transmitted large capacity of the information, rapid transmission speed,strong anti-interference ability, this makes communication system reliability and validity are has been greatly improved. Secondly, it can be used in medical field,the endoscope is made of optical fiber can help doctor to inspectdiseases of the stomach. Last but not least, fiber optic lighting can be used in the art field.
船公司名缩写及英文全称汇总
船公司简称与缩写 公司简称缩写 澳大利亚国家航运公司澳国航运 ANL 美国总统轮船私人有限公司美国总统 APL 邦拿美船务有限公司邦拿美 BNML 波罗的海航运公司波罗的海 BOL 中波轮船股份公司中波 C-P 南美邮船公司南美邮船 CLAN S.A. 南美智利国家航运公司智利航运 CCNI 中日国际轮渡有限公司中日轮渡 CHINJIF 天敬海运天敬海运 CK 法国达飞轮船公司达飞轮船 CMA 京汉海运有限公司京汉海运 CO-HEUNG 中国远洋集装箱运输有限公司中远集运 COSCO 朝阳商船有限公司朝阳商船 CHOYANG 达贸国际轮船公司达贸国际 DELIMAS
德国胜利航运公司德国胜利 SENATOR 埃及国际轮船公司埃及船务 EIL 长荣海运股份有限公司长荣海运 EVERGREEN 远东轮船公司远东轮船 FESCO 金发船务有限公司金发船务 GFNG 浩洲船务公司浩洲船务 HCSC 韩进海运有限公司韩进海运 HANJIN 香港航运有限公司香港海运 HKMSH 香港明华船务有限公司香港明华 HKMW 赫伯罗特船务有限公司赫伯罗特 HAPPAG-LLOYD 现代商船有限公司现代商船 HYUNDAI 上海海隆轮船有限公司海隆轮船 HNT 金华航运有限公司金华航运 JH 川崎汽船株式会社川崎汽船 K LINE 高丽海运株氏会社高丽海运 KMTC 七星轮船有限公司七星轮船 SSCL 上海育海航运公司育海航运 SYH 上海中福轮船公司中福轮船 SZFSC 墨西哥航运有限公司墨西哥航运 TMM 上海天海货运有限公司天海货运 TMSC 东航船务有限公司东航船务 TOHO 宁波泛洋船务有限公司宁波泛洋 TOS 阿拉伯联合国家轮船公司阿拉伯轮船 UASC 立荣海运股份有限公司立荣海运 UNIGLORY
最新光纤通信资料
光纤通信系统 第一章所谓光纤通信，就是用光作为信息的载体、以光纤作为传输介质的一种通信方式。通信系统的容量通常用比特率—距离积BL 表示，B 为比特率,L 为中继间距。 三种低损耗窗850nm、3dB/km；1310nm、0.4dB/km；1550nm、0.2dB/km 4、PDH和SDH各表示什么？其速率等级标准是什么？ 答：PDH表示准同步数字序列，即在低端基群采用同步，高次群复用采用异步；SDH表示同步数字序列。 PDH速率等级标准： SDH速率等级标准： STM-1：155.520Mbit/s STM-4：622.080 Mbit/s STM-16：2.5 Gbit/ STM-64：10 Gbit/s 3、光纤通信有哪些优点？ 答：1、频带宽，通信容量大 2、损耗低，中继距离长 3、抗电磁干扰 4、无串音干扰，保密性好 5、光纤线径细、重量轻、柔软 6、光纤的原材料资源丰富，用光纤可节约金属材料 7、光纤具有耐腐蚀力强、抗核幅射、能源消耗小等优点。 5 、图示光纤通信系统，解释系统基本结构。 答： 光纤通信系统由光发送机、光纤光缆与光接收机等基本单元组成。系统中包含一些互连与光信号处理部件，如光纤连接器、隔离器、调制器、滤波器、光开关及路由器等。在长距离系统中还设置有中继器(混合或全光)。
1.光纤由哪几部分构成？从横截面上看由三部分构成：纤芯、包层、涂敷层； 2、光纤中的纤芯折射率与包层折射率的关系？单模光纤和多模光纤中中两者的芯经一般分别为多少？ 答：纤芯折射率大于包层折射率； 单模光纤纤芯直径：2a=8μm ～１２μm ，包层直径：2b=125μm ；多模光纤纤芯直径：2a=50μm ，包层直径：2b=125μm 。 3、根据芯、包折射率分布及模式传播情况，指出有哪些典型形式光纤？ 答：按照折射率： 折射率在纤芯与包层介面突变的光纤称为阶跃光纤；折射率在纤芯内按某种规律逐渐降低的光纤称为渐变光纤。 按照传输模式： 单模光纤和多模光纤。 5、数值孔径NA 的物理意义？表达式是什么？ 答：光纤的数值孔径NA,它的含义是反映光纤对光信号的集光能力（接收能力），NA 值越大，对光信号集光（接收）能力越强。 NA ＝sin θ C ( 0001001sin sin(90)1sin cos c c n n n n n n n n NA n θθθθ=-=======∴=或或
船代常用的英文缩写
船代常用的英文缩写
船代常用英文缩写
1)ORC (Origen Recevie Charges) 本地收货费 用（广东省收取） (2)THC (Terminal Handling Charges) 码头操 作费（香港收取） (3)BAF (Bunker Adjustment Factor) 燃油附加 费 (4)CAF (Currency Adjustment Factor) 货币贬 值附加费 (5)YAS (Yard Surcharges)码头附加费 (6)EPS (Equipment Position Surcharges) 设 备位置附加费 (7)DDC (Destination Delivery Charges) 目的 港交货费 (8)PSS (Peak Season Sucharges) 旺季附加费 (9)PCS (Port Congestion Surcharge) 港口拥 挤附加费 (10)DOC (DOcument charges) 文件费 (11)O/F (Ocean Freight) 海运费 (12)B/L (Bill of Lading) 海运提单 铁路协会 ACEP Approved continuous examination programme 集装箱安全连续检验计划
AG Alantic and gulf base ports 美国东岸及 墨西哥湾基本港 AM Above mentioned 上述的 ASA American Standard Association 美国标准 协会 AW All water 全水路 B/C Bill of collection 托收汇票 B/L Bill of Lading 提单 BAF Bunker adjustment factor 燃油附加费BJG Beijing 北京 C&D Collected and delivered 运费已收及货物已交付 C&F Cost and freight 成本加运费加 C/O Certificate of Origin 产地证明书 CAF Currency adjustment factor 币值附加费CBM Cubic metre 立方米 CCC Customs Convention on Containers 集装箱海关公约 CFS Container freignt station 集装箱货运站CIF Cost,insurance and freight 成本加运费,加保险费
光纤通信RF方面的中英文翻译
RF和微波光纤设计指引 Name: Class: Student NO.:
RF and Microwave Fiber-Optic Design Guide Agere Systems Inc., through its predecessors, began developing and producing lasers and detectors for linear fiber-optic links nearly two decades ago. Over time, these optoelectronic components have been continually refined for integration into a variety of systems that require high fidelity, high frequency, or long-distance transportation of analog and digital signals. As a result of this widespread use and development, by the late 1980s, these link products were routinely being treated as standard RF and microwave components in many different applications. There are several notable advantages of fiber optics that have led to its increasing use. The most immediate benefit of fiber optics is its low loss. With less than 0.4 dB/km of optical attenuation, fiber-optic links send signals tens of kilometers and still maintain nearly the original quality of the input. The low fiber loss is also independent of frequency for most practical systems. With laser and detector speeds up to 18 GHz, links can send high-frequency signals in their original form without the need to downconvert or digitize them for the transmission portion of a system. As a result, signal conversion equipment can be placed in convenient locations or even eliminated altogether, which often leads to significant cost and maintenance savings. Savings are also realized due to the mechanical flexibility and lightweight fiber-optic cable, approximately 1/25 the weight of waveguide and 1/10 that of coax. Many transmission lines can be fed through small conduits, allowing for high signal rates without investing in expensive architectural supports. The placement of fiber cable is further simplified by the natural immunity of optical fiber to electromagnetic interference (EMI). Not only can large numbers of fibers be tightly bundled with power cables, they also provide a uniquely secure and electrically isolated transmission path. The general advantages of fiber-optics first led to their widespread use in long-haul digital telecommunications. In the most basic form of fiber-optic communications, light from a semiconductor laser or LED is switched on and off to send digitally coded information through a fiber to a photodiode receiver. By comparison, in linear fiber-optic systems developed by Lucent, the light sent through the fiber has an intensity directly related to the input electrical current. While this places extra requirements on the quality of the lasers and photodiodes, it has been essential in many applications to transmit arbitrary RF and microwave signals. As a result, tens of thousands of Agere Systems’ transmitters are currently in use. The information offered here examines the basic link components, provides an overview of design calculations related to gain, bandwidth, noise, and dynamic range
光纤通讯基础简介(上)
光纤通讯基础简介(上) 一、光通讯简介 1、使用光通讯技术的优点︰ 它是以光当作载波，透过光纤当传输介质将信息传递至远方。若以铜质同轴电缆与光纤作一比较，同轴电缆是搭配电磁波以数百MHz至数个GHz频率，以模拟的方式来传递信息，但其载波频率会受到20GHz理论值的限制；若以长距离光纤通讯而言，光的载波频率可达193,000GHz。而传输信息的频宽取决于载波频率，因此，若同轴缆线最大上限可以传输两个10GHz的频道，理论上，光纤则可以传输数以千计的10GHz的频道。此外，光纤质轻直径小，在光缆铺设过程中可以节省空间，加上在传输的过程中的衰减比铜质导线低，以单模光纤而言，每公里衰减约为0.2~0.5dB，且对于光讯号在光纤传输过程中，对于电磁波的干扰较不敏感，因此适合高容量及长距离通讯。 2、应用的层次︰ 光通讯主要应用在电信网络、有线电视及数据传输方面，而电信方面的应用是最早的，例如越洋的通信，因其高容量及可靠度的优点，并可以在长距离(600km以上需要中继器，最大可达9000km)传输时载上数以万计的通话信号，因而有效的提升通话负载量及品质的问题。有线电视方面，因所需求的频宽较高，每个频道的所需的影像频宽约为6MHz(声音频道约为8KHz)，以光纤传递模拟影像讯号，可以达到一百个以上的频道，其中包括声音、影像及互动的数据传输。而数据通信(Datacommunication)上面，则是现在最热门的话题，随着信息时代的来临，网际网络需要大量的频宽来传递多媒体的信息，从短距离(1~500m)的Gigabit网络卡、LAN，到中距离(1~20km)的MAN以至于长距离(60~600km以上)的越洋光缆都需要光纤的大容量来解决频宽不足的问题，近年来，因网际网络Interent的盛行及远距教学等实施，对于数据通讯的需求每年以倍数成长，而光纤通信系统架构则是最佳的选择。 3、基本光纤通讯架构︰ 图一为点对点光纤通讯的基本架构，基本上是由光收发模块及光纤所组成，首先我们利用数字或模拟调变的方式将信息载在发射器上，以光波为载波透过光纤将讯号传递至远方，若距离较长，光纤则透过联结器(Connector)或接合器(splice)方式延长，最后到达光传感器端，在注重噪声与讯号比(S/N Ratio)情况下，并用clock recover的方式下将光讯号转回电讯号，而将信息解调回来。
租船合同缩写
租船合同缩写 【篇一：租船合同缩写】 相关热词搜索： 篇一：租船协议中英文对照 fixture note it is mutually between the charterer and owner of the following：（租船人与船东协议如下）经友好协商双方打成如下条款： 1.charterer（租船人）： 2.owers（船东）： 3.vsl （船舶） 4.cargo（货物）： 5. part cargo acceptable（可以接受的部分货物）： 6.cargo to be loaded/disched by ro-ro only.n ows option to load cgo on weather deck （货物只是通过滚装来装卸，还是船东 自由把货物放在露天甲板上，） 7.l/port（装运港）: 8.d/port（卸货港）: ycan:（受载期） 10.loading/discharging rate（装卸率）: cqd bends按港口习惯速 度尽快装卸 11.freight（运费）:usd /cbm flt basis 1/1（美元/立方，） 12.payment:100pct of frt to be paid to owners nominated bank account w/i 3 banking days upon completion of loading and sr bl marked “frt payable as per cp”but always bbb.full freight to be deemed as earned with discountless and non-returnable on cargoes lost or not lost. 付款方式：全部运费在装完货和签发预付 运费提单后3个银行工作日内付至船东指定账户.所有运费在装完货 后即视为已赚取，不得扣减，无须返还，无论船舶和/或货物灭失与否。 13. bs/l: owners form to be used,owners/master to authorize l/port agent to sign/release bs/l in accordance with mate’s receipt.bs/l to be signed/releas ed marked “freight prepaid”upon full freight has been duly received by owners nominated bank.
光纤通信系统Optical_Fiber_Communications_英文资料及中文翻译
光纤通信系统 Optical Fiber Communications 英文资料及中文翻译 Communication may be broadly defined as the transfer of information from one point to another .When the information is to be conveyed over any distance a communication system is usually required .Within a communication system the information transfer is frequently achieved by superimposing or modulating the information on to an electromagnetic wave which acts as a carrier for the information signal .This modulated carrier is then transmitted to the required destination where it is received and the original information signal is obtained by demodulation .Sophisticated techniques have been developed for this process by using electromagnetic carrier waves operating at radio requites as well as microwave and millimeter wave frequencies. The carrier maybe modulated by using either optical an analog digital information signal.. Analog modulation involves the variation of the light emitted from the optical source in a continuous manner. With digital modulation, however, discrete changes in the length intensity are obtained (i.e. on-off pulses). Although often simpler to implement, analog modulation with an optical fiber communication system is less efficient, requiring a far higher signal to noise ratio at the receiver than digital modulation. Also, the linearity needed for analog modulation is mot always provided by semiconductor optical source, especially at high modulation frequencies .For these reasons ,analog optical fiber communications link are generally limited to shorter distances and lower bandwidths than digital links . Initially, the input digital signal from the information source is suitably encoded for optical transmission .The laser drive circuit directly modulates the intensity of the semiconductor last with the encoded digital signal. Hence a digital optical signal is launched into the optical fiber cable .The avalanche photodiode detector (APD) is followed by a front-end amplifier and equalizer or filter to provide gain as well as linear signal processing and noise bandwidth reduction. Finally ,the signal obtained is
租船简写(1)
AAAA = A LWAYS A FLOAT A LWAYS A CCESSIBLE AAOSA = A LWAYS A FLOAT O R S AFELY A GROUND ACOD = A FTER C OMPLETION O F D ISCHARGE ACOL = A FTER C OMPLETION O F L OADING ADA = A LL D ETAILS A BOUT A/E = A CCEPT/E XCEPT AFF = A FTER F ULLY F IXING AFMT = A FTER F IXING M AIN T ERMS AHL = A LTERNATIVE H OLD L OAD AHL = A USTRALIAN H OLD L ADDERS AOH = A FTER O FFICE H OURS APS = A RRIVAL P ILOT S TATION APS = A LL P URPOSE S APT = A FT P EAK T ANK AQIS = A USTRALIAN Q UARANTINE I NSPECTION S ERVICE ARA = A NTWERP / R OTTERDAM / A MSTERDAM ATA = A CTUAL T IME OF A RRIVAL ATB = A CTUAL T IME OF B ERTHING ATDNSHINC = A NY T IME D AY OR N IGHT S UNDAYS AND H OLIDAYS INC LUDED ATS = A LL T IME S AVED ATUTC = A CTUAL T IME U SED T O C OUNT AWIWL = A LWAYS W ITHIN I NSTITUTE W ARRANTY L IMITS BAF = B UNKER A DJUSTMENT F ACTOR BB = B ALLAST B ONUS BBB= B EFORE B REAKING B ULK BBC = B ARE B OAT C HARTER BCI = B ALTIC C APESIZE I NDEX BDI = B ATIC D RY I NDEX BDI = B OTH D ATES I NCLUSIVE BDMT = B OND D RIED M ETRIC T ONNE BE = B OTH E NDS BHP = B RAKE H ORSE P OWER BIMCO = B ALTIC AND I NTERNATIONAL M ARITIME CO NFERENCE BL = B ILL OF L ADING BOD = B UNKER O N D ELIVERY BOD = B OARD O F D IRECTORS BOP = B ALANCE O F P ERIOD BOR = B UNKER O N R EDELIVERY BPI = B ALTIC P ANAMAX I NDEX BSI = B ALTIC S UPRAMAX I NDEX BT = B ERTH T ERMS BTB = B ACK T O B ACK BTW = B Y T HE W AY
光纤通信中常用英文缩写
光纤通信中常用英文缩写( 光纤通信中常用英文缩写(2006-08-15 08:43:28)转载分类：课程相关知识 光纤通信中常用英文缩写Acronyms ac alternating current 交变电流交流 AM amplitude modulation 幅度调制 AON all-optical network 全光网络 APD avalanche photodiode 雪崩二极管 ASE amplified spontaneous emission 放大自发辐射 ASK amplitude shift keying 幅移键控 ATM asynchronous transfer mode 异步转移模式 BER bit error rate 误码率 BH buried heterostructure 掩埋异质结 BPF band pass filter 带通滤波器 C3 cleaved-coupled cavity 解理耦合腔 CATV common antenna cable television 有线电视 CDM code division multiplexing 码分复用 CNR carrier to noise ratio 载噪比 CSO Composite second order 复合二阶
CPFSK continuous-phase frequency-shift keying 连续相位频移键控CVD chemical vapour deposition 化学汽相沉积 CW continuous wave 连续波 DBR distributed Bragg reflector 分布布拉格反射 DFB distributed feedback 分布反馈 dc direct current 直流 DCF dispersion compensating fiber 色散补偿光纤 DSF dispersion shift fiber 色散位移光纤 DIP dual in line package 双列直插 DPSK differential phase-shift keying 差分相移键控 EDFA erbium doped fiber amplifier 掺铒光纤激光器 FDDI fiber distributed data interface 光纤数据分配接口 FDM frequency division multiplexing 频分复用 FET field effect transistor 场效应管 FM frequency modulation 频率调制 FP Fabry Perot 法布里里-珀落 FSK frequency-shift keying 频移键控 FWHM full width at half maximum 半高全宽 FWM four-wave mixing 四波混频 GVD group-velocity dispersion 群速度色散 HBT heterojunction-bipolar transistor 异质结双极晶体管 HDTV high definition television 高清晰度电视
常用的航运和租船英文缩写
常用航运和租船英语缩写 A always afloat 永远漂浮 AAR against all risks 针对所有风险 ABT about 大约 ACC acceptance/accepted 接受 ACCDG according to 根据 ACCT account 帐，因为 ACOL after completion of loading 装货结束后 ADDCOM address commission 回扣佣金 ADV advise 告知 AFLWS as follows 如下 AGT agent 代理人 AGW all goes well 一切顺利 AHPS arrival harbor pilot station 到达港口引航站 ANCH anchorage 锚地 ANS answer 回答 A/O and / or 和/或 AOH after office hours 工作时间外 AP additional premium 附加保险费 APS arrival pilot station 到达引航站 ARR arrive 到达 ASAP as soon as possible 尽可能快的 ASPS arrival sea pilot station 到达海区引航站 ATA actual time of arrival 实际到达时间 ATD actual time of departure 实际开航时间 ATDNSHINC any time,day,night,Sunday and holodays included 包括任何时间，白天黑夜星期六和节假日 ATDNSHEX any time,day,night,Sunday and holodays excepted 任何时间，白天，夜间星期六和节假日除外 ATS all time saved 所有节省时间 ATSBE all time saved both ends 所有两港节省时间 ATSDO all time saved discharging only 所有卸货港节省时间 ATSLO all time saved loading only 所有装货港节省时间 AWTS all working time saved 所有节省的工作时间 AWTSBE all working time saved both ends 所有两港节省的时间 AWTSDO all working time saved discharging only 所有卸货港节省的时间AWTSLO all working time saved loading only 所有装货港节省的时间 BB ballast bonus 空航奖金（空放补贴） BBB before breaking bulk 卸货前 B/D breakdown 故障 BENDS both ends 两端（装港和卸港） BIMCO baltic international maritime conference 波罗的海国际航运公会 BIZ business 业务 B/L bill of lading 提单
光纤通信中常用英文缩写备课讲稿
光纤通信中常用英文 缩写
光纤通信中常用英文缩写( 光纤通信中常用英文缩写(2006-08-15 08:43:28)转载分类：课程相关知识 光纤通信中常用英文缩写Acronyms ac alternating current 交变电流交流 AM amplitude modulation 幅度调制 AON all-optical network 全光网络 APD avalanche photodiode 雪崩二极管 ASE amplified spontaneous emission 放大自发辐射 ASK amplitude shift keying 幅移键控 ATM asynchronous transfer mode 异步转移模式 BER bit error rate 误码率 BH buried heterostructure 掩埋异质结 BPF band pass filter 带通滤波器 C3 cleaved-coupled cavity 解理耦合腔 CATV common antenna cable television 有线电视 CDM code division multiplexing 码分复用 CNR carrier to noise ratio 载噪比 CSO Composite second order 复合二阶
CPFSK continuous-phase frequency-shift keying 连续相位频移键控CVD chemical vapour deposition 化学汽相沉积 CW continuous wave 连续波 DBR distributed Bragg reflector 分布布拉格反射 DFB distributed feedback 分布反馈 dc direct current 直流 DCF dispersion compensating fiber 色散补偿光纤 DSF dispersion shift fiber 色散位移光纤 DIP dual in line package 双列直插 DPSK differential phase-shift keying 差分相移键控 EDFA erbium doped fiber amplifier 掺铒光纤激光器 FDDI fiber distributed data interface 光纤数据分配接口 FDM frequency division multiplexing 频分复用 FET field effect transistor 场效应管 FM frequency modulation 频率调制 FP Fabry Perot 法布里里-珀落 FSK frequency-shift keying 频移键控 FWHM full width at half maximum 半高全宽 FWM four-wave mixing 四波混频 GVD group-velocity dispersion 群速度色散 HBT heterojunction-bipolar transistor 异质结双极晶体管 HDTV high definition television 高清晰度电视
空间光通信技术简介
空间光通信技术简介 空间光通信又称为激光无线通信或无线光通信。根据用途又可分为卫星光通信和大气光通信两大类。自从60年代激光器问世开始，人们就开研究激光通信，这时的研究也主要集中在地面大气的传输中，但因各种困难未能进入实际应用。低损耗光纤波导和实用化半导体激光器的诞生为激光通信的实际应用打开了大门，目前光纤通信已经遍布世界各国的各个城市。由于对无线通信的需求的增长，再有卫星激光通信的快速发展，自从90年代开始，人们又开始重新对地面无线光通信感兴趣，进行了大量的研究，并且开发出可以实用的商业化产品。 一、开展空间光通信研究的意义及应用前景 1.作为卫星光通信链路地面模拟系统的技术组成部分 卫星光通信链路系统在上卫星前必须有地面模拟演示系统，以保障电子系统、光学系统、机械自动化控制系统等各子系统的良好工作。在链路捕捉完成以后，与以太网相连的无线光通信系统借助于光链路的桥梁，源源不断地输送以太网上的信息，这是考验光链路稳定性能的重要指标。 2.为低轨道卫星与地面站间的卫星光通信打下良好的技术基础 低轨道卫星与地面站的通信会受到天气的影响，选择干旱少雨地区建立地面站在相当程度上缓解了这一矛盾，再通过地面站之间的光纤网可以把卫星上信息送到所需地点，这从技术上牵涉到空间光通信网与光纤网连接问题，这方面问题已经基本得到解决。 3.空间光通信具有巨大的潜在市场和商业价值 ●可以克服一些通常容易碰到的自然因素障碍 当河流、湖泊、港湾、马路、立交桥和其它自然因素阻碍铺设光纤时，无线光通信系统可跨越宽阔的河谷，繁华的街道，将两岸或者岛屿与陆地连接起来。 ●提供大容量多媒体宽带网接入 用无线光通信系统作为接入解决方案，不需耗资、耗时地铺设光纤就能满足对办公大楼或商业集中区大容量接入的需要。 ●可为大企业、大机关提供部大容量宽带网 无线光通信系统能在企业、机关围为建筑物与建筑物之间的大容量连接提供一种开放空间传送的解决方案。 ●为公安、军队等重要部门提供高速宽带通信。 ●支持灾难抢救的应急系统 无线光通信系统可为灾难抢救提供一种大容量的临时通信解决方案 ●为一时性大规模的重要活动提供临时的大规模通信系统 例如，奥运会和其他体育运动会、音乐会、大型会议以及贸易展览会等专门活动往往需要大容量宽带媒体覆盖。无线光通信系统能提供一种迅速、经济而有效的解决方案，不受原有通信系统的带宽限制，也不用再去办理光纤铺设许可证。 二、空间光通信的优势 1.组网机动灵活 无线光通信设备将来可广泛适用于数据网（Ethernet，Token Ring，Fast Ethernet，FDDI，ATM,STM-x等）、网、微蜂窝及微微蜂窝（E1/T1—E3/T3，OC-3等）、多媒体（图像）通信等领域。可以把这些网上信息加载在光波上，在空气中直接传输出去，这种简便的通信方式对于频率拥挤的环境是非常理想的，例如：城市、大型公司、大学、政府机构、办公楼群等。
货代知识货代常用英文缩写
【货代知识】货代常用英文缩写 1. IGO inter-government organization 政府间国际组织 2. NGO non-government organization 非政府间国际组织 3. ICS international chamber shipping 国际航运公会 4. BIMCO Baltic and international maritime council 波罗的海国际海事协会 5. CMI committee maritime international 国际海事委员会 6. IMO international maritime organization 国际海事组织 7. LNG liquified natural gas 液化天然气 8. LPG liquified petroleum gas液化石油气 9. SF stowage factor 货物积载因数 10. IMDG Code international maritime dangerous goods code 国际海运危险货物规则 11. ISO international standard organization 国际标准化组织 12. SOC shipper's own container 货主箱 13. COC carrier's own container船公司箱 14. TEU twenty-foot equivalent units 计算单位,也称20英尺换算单位 15. FCL full container load整箱货 16. LCL less container load 拼箱货 17. CY container yard集装箱堆场 18. CFS container freight station 集装箱货运站 19. DOOR 货主工厂或仓库 20. DPP damage protection plan 损害修理条款 21. SC service contract 服务合同
光纤通信实验资料报告材料
实验1 数字发送单元指标测试实验 一、实验目的 1.了解数字光发端机平均输出光功率的指标要求 2.掌握数字光发端机平均输出光功率的测试方法 3.了解数字光发端机的消光比的指标要求 4.掌握数字光发端机的消光比的测试方法 二、实验仪器 1.ZYE4301G型光纤通信原理实验箱1台 2.光功率计1台 3.FC/PC-FC/PC单模光跳线1根 4.示波器1台 5.850nm光发端机1个 6.ST/PC-FC/PC多模光跳线1根 三、实验原理 四、实验容 1.测试数字光发端机的平均光功率 2.测试数字光发端机的消光比 3.比较驱动电流的不同对平均光功率和消光比的影响 五、实验步骤 Ａ、1550nm数字光发端机平均光功率及消光比测试 1.伪随机码的产生：伪随机码由CPLD下载模块产生，请参看系统简介中的CPLD下载模块。将PCM编译码模块的4.096MH Z时钟信号输出端T661与CPLD下载模块的NRZ信号产生电路的信号输入端T983连接，NRZ信号输出端T980将产生4M速率24－1位的伪随机信号，用示波器观测此信号。将此信号与1550nm光发模块输入端T151连接，作为信号源接入1550nm光发端机。 2.用FC-FC光纤跳线将光发端机的输出端1550T与光功率计连接，形成平均光功率测试系统，调整光功率计，使适合测1550nm信号。 3.用K60、K90和K15接通PCM编译码模块、CPLD模块和光发模块的电源。 4.用光功率计测量此时光发端机的光功率，即为光发端机的平均光功率。 5.测消光比用数字信号源模块输出的NRZ码作为信号源。用K60接通电源，用用示波器从T504观测此信号，将K511接1、2或2、3可观测到速率的变化，将此信号接到T151，作为伪随机信号接入光发端机。 6.用数字信号源模块的K501、K502、K503将数字信号拨为全“1”，测得此时光功率为P1，将数字信号拨为全“0”，测得此时光功率为P0。 7.将P1，P0代入公式2-1式即得1550nm数字光纤传输系统消光比。 Ｂ、1310nm数字发端机平均光功率及消光比测试 8.信号源仍用4M速率24－1位的伪随机信号，与1310nm光发模块输入端T101连接。 9.用FC-FC光纤跳线将1310nm光发模块输出端1310T与光功率计连接，形成平均光功率测试系统，调整光功率计，使适合测1310nm信号。 10.将BM1拨至数字，BM2拨至1310nm。 11.接通PCM编译码模块、CPLD模块和1310nm光发模块(用K10)的电源。 12.用万用表在T103和T104监控R110（阻值为1Ω）两端电压，调节电位器W101，使半导体激光器驱动电流为额定值25mA。 13.用光功率计测量此时光发端机的光功率，即为光发端机的平均光功率。 14.测消光比用数字信号源模块输出的NRZ码作为信号源，请参看系统简介中的数字信号源模块部分。用示波器从T504观测此信号，连接T504与T101，将数字信号拨为全“1”，测得此时光功率为P1，将数字信号拨为全“0”，测得此时光功率为P0。 15.将P1，P0代入公式2-1式即得1310nm数字光纤传输系统消光比。 16.重复9-15步，调节电位器W101，调节驱动电流大小为下表中数值时，测得的平均光功率及消 光比填入下表。