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)?
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