Copyright © NDSL, Chang Gung University. Permission required for reproduction or display. Chapter 7 Transmission Media 長庚大學資訊工程學系 陳仁暉 副教授 Tel: (03) 211-8800.

Présentation au sujet: "Copyright © NDSL, Chang Gung University. Permission required for reproduction or display. Chapter 7 Transmission Media 長庚大學資訊工程學系 陳仁暉 副教授 Tel: (03) 211-8800."— Transcription de la présentation:

1 Copyright © NDSL, Chang Gung University. Permission required for reproduction or display. Chapter 7 Transmission Media 長庚大學資訊工程學系 陳仁暉 副教授 Tel: (03) 211-8800 Ext: 5990 Email: jhchen@mail.cgu.edu.tw URL: http://www.csie.cgu.edu.tw/~jhchen

2 NDSLab Copyright@2008 2 Figure 7.1 Transmission medium and physical layer

3 NDSLab Copyright@2008 3 Transmission Media By definition –Broadly defined as anything that can carry information from a source to a destination. –e.g., air, twisted-pair cable, coaxial cable, fiber-optic cable, conductor, and so on. Guided media –Provide a conduit from one device to another, include twisted-pair cable, coaxial cable, and fiber-optic cable.

4 NDSLab Copyright@2008 4 Figure 7.2 Classes of transmission media

5 NDSLab Copyright@2008 5 7-1 GUIDED MEDIA Guided media, which are those that provide a conduit from one device to another, include twisted-pair cable, coaxial cable, and fiber-optic cable. Twisted-Pair Cable Coaxial Cable Fiber-Optic Cable Topics discussed in this section:

6 NDSLab Copyright@2008 6 Figure 7.3 Twisted-pair cable

7 NDSLab Copyright@2008 7 Figure 7.4 UTP and STP cables Unshielded Twisted-Pair (UTP)Shielded Twisted-Pair (STP)

8 NDSLab Copyright@2008 8 Unshielded vs Shielded Twisted-Pair Cable Unshielded twisted-pair (UTP) Shielded twisted-pair (STP) –Has a metal foil or braided-mesh covering that encases each pair of insulated conductors. Category –Electronic Industries Association (EIA) has developed standards to classify unshielded twisted-pair cable into seven categories. Table 7.1 shows these categories. Connectors –Most common UTP connector is RJ-45 (RJ stands for registered jack).

9 NDSLab Copyright@2008 9 Table 7.1 Categories of unshielded twisted-pair cables

10 NDSLab Copyright@2008 10 Figure 7.5 UTP connector

11 NDSLab Copyright@2008 11 Figure 7.6 UTP performance Gauge is a measure of the thickness of the wire.

12 NDSLab Copyright@2008 12 Figure 7.7 Coaxial cable

13 NDSLab Copyright@2008 13 Table 7.2 Categories of coaxial cables

14 NDSLab Copyright@2008 14 Figure 7.8 BNC connectors

15 NDSLab Copyright@2008 15 Figure 7.9 Coaxial cable performance

16 NDSLab Copyright@2008 16 Figure 7.10 Bending of light ray

17 NDSLab Copyright@2008 17 Figure 7.11 Optical fiber

18 NDSLab Copyright@2008 18 Figure 7.12 Propagation modes

19 NDSLab Copyright@2008 19 Figure 7.13 Modes

20 NDSLab Copyright@2008 20 Table 7.3 Fiber types

21 NDSLab Copyright@2008 21 Figure 7.14 Fiber construction

22 NDSLab Copyright@2008 22 Figure 7.15 Fiber-optic cable connectors

23 NDSLab Copyright@2008 23 Figure 7.16 Optical fiber performance

24 NDSLab Copyright@2008 24 7-2 UNGUIDED MEDIA: WIRELESS Unguided media transport electromagnetic waves without using a physical conductor. This type of communication is often referred to as wireless communication. Radio Waves Microwaves Infrared Topics discussed in this section:

25 NDSLab Copyright@2008 25 Figure 7.17 Electromagnetic spectrum for wireless communication

26 NDSLab Copyright@2008 26 Figure 7.18 Propagation methods

27 NDSLab Copyright@2008 27 Table 7.4 Bands

28 NDSLab Copyright@2008 28 Figure 7.19 Wireless transmission waves

29 NDSLab Copyright@2008 29 Figure 7.20 Omnidirectional antenna

30 NDSLab Copyright@2008 30 Radio waves are used for multicast communications, such as radio and television, and paging systems. Note

31 NDSLab Copyright@2008 31 Figure 7.21 Unidirectional antennas

32 NDSLab Copyright@2008 32 Microwaves are used for unicast communication such as cellular telephones, satellite networks, and wireless LANs. Note

33 NDSLab Copyright@2008 33 Infrared signals can be used for short- range communication in a closed area using line-of-sight propagation. Note