Komunikasi Data (TEU 611)

Transmission Media

Dr. I Wayan Mustika, ST., M.Eng.

Jurusan  Teknik  Elektro  dan  Teknologi  Informasi    FT  UGM  

Outline

Ø Guided Media Ø Twisted-pair cable Ø Coaxial cable Ø Fiber-optic cable

Ø Unguided Media: Wireless Ø Radio waves Ø Microwaves Ø Infrared

Transmission Medium and Physical Layer

q Definition Anything that can carry information from source to destination

Classes of Transmission Media

Twisted-Pair Cable

§  Consists of two conductors (normally cooper), each with its own plastic insulation

UTP vs STP

Categories of UTP Cables Category Bandwidth Data Rate Digital/Analog Use

1 very low < 100 kbps Analog Telephone

2 < 2 MHz 2 Mbps Analog/digital T-1 lines

3 16 MHz 10 Mbps Digital LANs

4 20 MHz 20 Mbps Digital LANs

5 100 MHz 100 Mbps Digital LANs

5E 125 MHz 125 Mbps Digital LANs

6 200 MHz 200 Mbps Digital LANs

7 600 MHz 600 Mbps Digital LANs

UTP Connector

http://en.wikipedia.org/wiki/Category_6_cable

UTP Performance

Coaxial Cable

§  Can carries signals of higher frequency ranges than those in twisted-pair cable

Categories of Coaxial Cables

Category Impedance Use

RG-59 75 Ω Cable TV

RG-58 50 Ω Thin Ethernet

RG-11 50 Ω Thick Ethernet

Coaxial Cable Connectors

§  BNC connectors

Performance of Coaxial Cable

Fiber-Optic Cable

§  Bending of light ray

Optical Fiber

Propagation Modes

Modes

Fibre Types

Type Core (µm) Cladding (µm) Mode

50/125 50 125 Multimode, graded-index

62.5/125 62.5 125 Multimode, graded-index

100/125 100 125 Multimode, graded-index

7/125 7 125 Single-mode

Fibre Construction

Fibre-Optic Cable Connectors

Advantages and Disadvantages

Ø Advantages §  Higher bandwidth (data rates) §  Less signal attenuation §  Immunity to electromagnetic interference §  Resistance to corrosive materials §  Light Weight §  Greater immunity to tapping

Ø Disadvantages §  Installation and maintenance §  Unidirectional light propagation §  Cost

Unguided Media: Wireless

§  Electromagnetic spectrum for wireless communication

Propagation Methods

Band Range Propagation Application

VLF 3–30 KHz Ground Long-range radio navigation

LF 30–300 KHz Ground Radio beacons and navigational locators

MF 300 KHz–3 MHz Sky AM radio

HF 3–30 MHz Sky Citizens band (CB), ship/aircraft communication

VHF 30–300 MHz Sky and line-of-sight

VHF TV, FM radio

UHF 300 MHz–3 GHz Line-of-sight UHF TV, cellular phones, paging, satellite

SHF 3–30 GHz Line-of-sight Satellite communication

EHF 30–300 GHz Line-of-sight Long-range radio navigation

Wireless Transmission Waves

§  Radio waves: 3 kHz – 1 GHz §  Microwaves: 1 – 300 GHz §  Infrared: 300 GHz – 400 THz

Radio Waves

§  Radio waves use omnidirectional antennas that send out signals in all directions

Microwaves

§  Microwaves need unidirectional antennas that send out signals in one direction

§  Microwaves are used for unicast communication such as cellular telephones, satellite networks, and wireless LANs

Infrared

§  Infrared cannot penetrate walls §  Infrared signals can be used for short-range

communication in a closed area using line-of-sight propagation

Assignment 2

1.  Using Figure of performance of coaxial cable, tabulate the attenuation (in dB) of a 2.6/9.5 mm coaxial cable for the indicated frequencies and distances. Distance: 1 Km, 10 Km, 15 Km, and 20 Km. Right column: dB at 1 kHz, 10 kHz, and 100 kHz. •  If the power at the beginning of a 1 Km 2.6/9.5 mm

coaxial cable is 200 mw, what is the power at the end for frequencies 1 KHz, 10KHz, and 100 KHz?

1.  A light signal is travelling through a fiber. What is the delay in the signal if the length of the fiber-optic cable is 10 m, 100 m, and 1 Km (assume a propagation speed of 2 x 108 m)?