足彩app哪个是正规的

Popular Search Graduation Thesis Nursing Graduation Thesis Graduate Graduation Thesis E-commerce Thesis Undergraduate Graduation Thesis References Chinese Economic Paper

计算机论文 > 通信技术论文 Papers > Computer Papers > Communication Technology Papers

Communication graduation thesis model

编辑: 毕业论文 Release time: 2016-08-29 Editor: Graduation Thesis

Abstract: The paper introduces the development and composition of optical fiber communication system monitoring, briefly introduces the principle of test instrument OTDR, and maintenance cases of optical fiber communication systems.

Keywords: fiber optic communication, monitoring, case

1 Status of fiber optic cables

1.1 Scale and Technology

As optical fiber communication has the advantages of large capacity, high quality of transmitted information, long transmission distance, stable performance, strong electromagnetic interference resistance, and strong anti-corrosion capabilities, it has been accompanied by "optical advancement and copper withdrawal" to complete the construction. The horizontal & quot; optical cable transmission network connects 31 provinces (autonomous regions, municipalities directly under the Central Government) across the country. The optical fiber cable communication network has become China's main transmission network. On the other hand, with the rapid development of optical synchronous digital transmission network (SDH), packet transmission technology (PTN) and dense wavelength division multiplexing (DWDM) technology, the transmission capacity of optical fiber is also developing at an unprecedented speed.

1.2 Cause of failure

The optical fiber is made of very fragile glass. Generally, the core of a single-mode fiber with an outer diameter of 125um is only 7-8um, and the core of a multimode fiber is only 50um. Although the fiber cable itself uses FBT to strengthen the core, grease and plastic The outer sheath protects the optical fiber, so that the optical cable has a certain resistance to external forces. However, due to the savage construction, strong external force impact, and other factors such as cracking of the junction box, water ingress, corrosion, and natural aging of the optical fiber cable, the failure of the optical fiber cable transmission system often occurs. Optical cable lines and laying are through underground buried, overhead and pipelines, etc., have the characteristics of multiple points, line length, wide area, highly dispersed, and are greatly affected by external forces. Blocking obstacles caused by external reasons of the optical cable itself involve optical cables. During the expansion, relocation, modification, and relocation of the optical cable line, maintenance and more are difficult and difficult. How to quickly detect fiber cables and locate faults has become a necessary skill for communication engineers or technicians.

2 Fiber optic system monitoring

Optical cable line automatic monitoring system is mainly composed of provincial monitoring center PMC, regional monitoring center LMC, and on-site monitoring station MS. The monitoring center is responsible for controlling the monitoring stations. It is a center for collecting and processing data. It consists of controllers (servers, clients, workstations), routers, hubs / switching hubs, network adapters, modems, printers and corresponding software. .

In long-distance and city relay optical fiber cable transmission systems, the transmission equipment is equipped with bit error rate (BER) monitoring equipment or monitoring units. However, the traditional line maintenance department is not equipped with monitoring means, usually only when a BER alarm occurs, the crew first determines the cause of the alarm, and after the cause is identified as the transmission line-fiber optic cable, the crew will notify The relevant line maintenance department and the relevant competent authority are reported, and then the line maintenance department takes corresponding maintenance measures based on the degradation of the transmission performance of the optical fiber cable. If an optical fiber breakage obstacle occurs, immediately send personnel to carry an instrument (OTDR) to find the location of the optical fiber breakage, and at the same time organize personnel, machinery, equipment, etc. for repair, which is commonly referred to as obstacle repair; if it occurs, the total attenuation of the fiber channel increases When its value is allowable, it is included in the line maintenance and renovation plan, and when it is not acceptable, it is organized to repair it in order to improve its transmission performance and provide a reliable circuit.

3 OTDR

OTDR (optical time domain reflectometer) is the main tool for testing optical cable obstacles during maintenance. It is used to test the position of the optical cable breakpoint so that repair personnel can arrive at the site in time for emergency repair. It uses backscatter to measure the loss in the fiber. For the measurement of optical fiber loss, the OTDR uses the principle of sampling integration and optical pulse excitation to sample and analyze the optical signal transmitted in the optical fiber to determine the splice point and loss change point in the optical fiber. The principle is shown in Figure 1.

2 3 下一页 Previous 1 2 3 Next

Hot spot ranking
Recommended reading

The graduation thesis website provides the latest graduation thesis topics, graduation thesis opening report , graduation thesis acknowledgment , graduation thesis defense , graduation thesis writing format , graduation thesis references, etc. At the same time, it also provides university students with the best and most comprehensive graduation thesis essays , graduation speeches , graduation messages , graduation gifts, and so on.

Some of the resources of the Graduation Thesis Network come from the Internet. The copyright of the content belongs to the original author. If there is any infringement, please let us know and we will deal with it immediately.

Graduation Thesis Website Sitemap TAG Tag Henan ICP No. 17024122-1