Jaringan Telekomunikasi: Reference: Juhana,tutun.(2013). Transmissionmedia [powerpointslides].itb

JARINGAN TELEKOMUNIKASI

R E F E RENCE: JU HA N A , T UT UN . ( 2 0 1 3) . T R A N SM ISSI O N M E DI A [ P OW E R POINT S L I DES] . I T B.

Tipe-tipe Media Transmisi Guided transmission media ◦ Kabel tembaga ◦ Open Wires ◦ Coaxial ◦ Twisted Pair

◦ Kabel serat optik

Unguided transmission media ◦ infra merah ◦ gelombang radio ◦ microwave: terrestrial maupun satellite

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Guided Transmission Media WAVES ARE GUIDED ALONG SOLID MEDIUM

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Kabel Tembaga  Paling lama dan sudah biasa digunakan  Kelemahan: redaman tinggi dan sensitif terhadap interferensi

 Redaman pada suatu kabel tembaga akan meningkat bila frekuensi dinaikkan  Kecepatan rambat sinyal di dalam kabel tembaga mendekati 200.000 km/detik

 Tiga jenis kabel tembaga yang biasa digunakan:  Open wire  Coaxial  Twisted Pair

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Open wire Sudah jarang digunakan Kelemahan: ◦ Terpengaruh kondisi cuaca dan lingkungan ◦ Kapasitas terbatas (hanya sekitar 12 kanal voice)

70 miles open wire from Hawthorne to Tonopah Photograph taken by Brian Hayes in 1999 (http://flickr.com/photos/brianhayes/321552411/)

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Coaxial • Bandwidth lebar (45-500 MHz) • Lebih kebal terhadap interferensi • Contoh penggunaan : pada antena TV, LAN dsb. (D) (C) (B) (A)

RG58 coax and BNC Connector

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Twisted pair

Twisted pair dibangun dari dua konduktor yang dipilin ◦ Kabel dipilin untuk mengeliminasi crosstalk

Pada suatu bundel twisted pair (lebih dari satu pasang), twist length (twist rates) masing-masing pasangan dibedakan untuk mencegah crosstalk antar pasangan Pengiriman sinyal pada twisted pair menggunakan “balance signaling” untuk mengeliminasi pengaruh interferensi (noise)

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Twisted pairs Types Unshielded Twisted pair (UTP)

Shielded Twisted pair (STP)

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Unshielded Twisted pair (UTP)

Category 1- originally designed for voice telephony only, but thanks to some new techniques, long-range Ethernet and DSL, operating at 10Mbps and even faster, can be deployed over Cat 1 Category 2 - accommodate up to 4Mbps and is associated with token-ring LANs. Category 3 - Cat 3 cable operates over a bandwidth of 16MHz on UTP and supports up to 10Mbps over a range of 330 feet (100 m). ◦ Key LAN applications include 10Mbps Ethernet and 4Mbps token-ring LANs.

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UTP Category 4 ◦ operates over a bandwidth of 20MHz on UTP ◦ can carry up to 16Mbps over a range of 330 feet (100 m). ◦ The key LAN application is 16Mbps token ring.

Category 5 ◦ operates over a bandwidth of 100MHz on UTP ◦ Can handle up to 100Mbps over a range of 330 feet (100m). ◦ Cat 5 cable is typically used for Ethernet networks running at 10Mbps or 100Mbps. ◦ Key LAN applications include 100BASE-TX, ATM, CDDI, and 1000BASET. ◦ It is no longer supported, having been replaced by Cat 5e.

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UTP Category 5e ◦ Cat 5e (enhanced) operates over a bandwidth of 100MHz on UTP, with a range of 330 feet (100 m). ◦ The key LAN application is 1000BASE-T. ◦ The Cat 5e standard is largely the same as Category 5, except that it is made to somewhat more stringent standards. ◦ Category 5e is recommended for all new installations and was designed for transmission speeds of up to 1Gbps (Gigabit Ethernet). ◦ Although Cat 5e can support Gigabit Ethernet, it is not currently certified to do so.

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UTP Category 6 - specified under ANSI/TIA/EIA-568-B.2-1, ◦ Operates over a bandwidth of up to 400MHz ◦ Supports up to 1Gbps over a range of 330 feet (100 m). ◦ Cable standard for Gigabit Ethernet and other network protocols that is backward compatible with the Cat 5/5e and Cat 3 cable standards. ◦ Cat 6 features more stringent specifications for crosstalk and system noise. ◦ Cat 6 is suitable for 10BASE-T/100BASE-TX and 1000BASE-T (Gigabit Ethernet) connections.

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Shielded Twisted Pair (STP) Twisted pair cables are often shielded in attempt to prevent electromagnetic interference. Because the shielding is made of metal, it may also serve as a ground. However, usually a shielded or a screened twisted pair cable has a special grounding wire added called a drain wire. This shielding can be applied to individual pairs, or to the collection of pairs. When shielding is applied to the collection of pairs, this is referred to as screening. The shielding must be grounded for the shielding to work.

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STP (cont.) Screened unshielded twisted pair (S/UTP) Also known as Fully shielded (or Foiled) Twisted Pair (FTP), is a screened UTP cable (ScTP).

Shielded twisted pair (STP or STP-A) Screened shielded twisted pair (S/STP or S/FTP)

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Screened unshielded twisted pair (S/UTP)

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Shielded twisted pair (STP or STP-A)

1 – Jacket 2 – Shield-foil 3 – Drain wire 4 – Solid twisted pair

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Screened shielded twisted pair (S/STP or S/FTP) 1 – Jacket 2 – Rip-cord 3 – Shield-foil 4 – Drain wire 5 – Protective skin 6 – Polymer tape 7 – Solid twisted pair

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Optical Fiber JARINGAN TELEKOMUNIKASI

Optical Fiber Advantages

Weight and Size ◦ Fiber cable is significantly smaller and lighter than electrical cables to do the same job Material Cost ◦ Fiber cable costs significantly less than copper cable for the same transmission capacity Information Capacity ◦ Recently, bit-rates of up to 14 Tbit/s have been reached over a single 160 km line using optical amplifiers No Electrical Connection ◦ Electrical connections have problems: ◦ Ground loops (in a conductor connecting two points that are supposed to be at the same potential, often ground, but are actually at different potentials) causing noises and interferences ◦ Dangerous (must be protected) ◦ Lightning poses a severe hazard No Electromagnetic Interference ◦ Because the connection is not electrical, you can neither pick up nor create electrical interference (the major source of noise) Longer distances between Regenerators (hundreds of kilometers) Open Ended Capacity ◦ The maximum theoretical capacity of installed fiber is very great (almost infinite) Better Security ◦ It is possible to tap fiber optical cable. But it is very difficult to do and the additional loss caused by the tap is relatively easy to detect JARINGAN TELEKOMUNIKASI

Optical Fiber Elements Core ◦ Carries the light signal (pure silica glass and doped with germanium)

Cladding ◦ Keeps light signal within core (Pure Silica Glass)

Coating ◦ Protects Optical Fiber From Abrasion and External Pressures (UV Cured Acrylate)

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Mengapa cahaya bisa bergerak sepanjang serat optik? Karena ada fenomena Total Internal Reflection (TIR) TIR dimungkinkan dengan membedakan indeks bias (n) antara core dan clading ◦ Dalam hal ini ncore > ncladding ◦ Memanfaatkan hukum Snellius

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Remembering Snellius ncore > ncladding

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Critical angle ◦ At the critical angle we know that q² equals 90° and sin 90° = 1 and so

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Transmitter Light Sources Light Emitting Diodes (LED) ◦ ◦ ◦ ◦ ◦

Used for multimode: 850 nm or 1300 nm Wide beam width fills multimode fibers Wider spectrum (typically 50 nm) Inexpensive Cannot modulate as fast as lasers

VCSEL’s–Vertical Cavity Surface Emitting Laser ◦ ◦ ◦ ◦

Used for multimode at 850 and 1300 nm Quite narrow spectrum Narrow beam width (does not fill multimode fibers) Much less expensive than FP or DFB lasers

Fabry-Perot (FP) and Distributed Feedback (DFB) Lasers ◦ ◦ ◦ ◦

Used for singlemode: 1310 nm or 1550 nm Narrow spectrum (can be less than 1 nm) Narrow beam width (does not fill multimode fibers) Highest power and fastest switching–Most expensive (especially DFB)

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Salah satu cara untuk mengidenifikasi konstruksi kabel optik adalah dengan menggunakan perbandingan antara diameter core dan cladding. Sebagai contoh adalah tipe kabel 62.5/125. Artinya diamater core 62,5 micron dan diameter cladding 125 micron Contoh lain tipe kabel:50/125, 62.5/125 dan 8.3/125 Jumlah core di dalam satu kabel bisa antara 4 s.d. 144

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Klasifikasi Serat Optik Berdasarkan mode gelombang cahaya yang berpropagasi pada serat optik ◦ Multimode Fibre ◦ Singlemode Fibre

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Fiber Optic Installation Safety Rules Keep all food and beverages out of the work area. If fiber particles are ingested they can cause internal hemorrhaging Wear disposable aprons to minimize fiber particles on your clothing ◦ Fiber particles on your clothing can later get into food, drinks, and/or be ingested by other means Always wear safety glasses with side shields and protective gloves Treat fiber optic splinters the same as you would glass splinters. Never look directly into the end of fiber cables until you are positive that there is no light source at the other end ◦ Use a fiber optic power meter to make certain the fiber is dark. When using an optical tracer or continuity checker, look at the fiber from an angle at least 6 inches away from your eye to determine if the visible light is present.. Only work in well ventilated areas Contact wearers must not handle their lenses until they have thoroughly washed their hands. Do not touch your eyes while working with fiber optic systems until they have been thoroughly washed Keep all combustible materials safely away from the curing ovens Put all cut fiber pieces in a safe place. Thoroughly clean your work area when you are done Do not smoke while working with fiber optic systems. Source: http://www.jimhayes.com/

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Unguided Transmission Media PROVIDES A MEANS FOR TRANSMIT TING ELECTROMAGNETIC SIGNALS THROUGH THE AIR BUT DO NOT GUIDE THEM (WIRELESS TRANSMISSION)

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Electromagnetic Spectrum for Wireless Communication

Radio wave and microwave

3 kHz

Infra Red

300 GHz

Light wave

400 THz

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900 THz

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Transmission and reception are achieved by means of antennas ◦ For transmission, an antenna radiates electromagnetic radiation in the air ◦ For reception, the antenna picks up electromagnetic waves from the surrounding medium ◦ The antenna plays a key role

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Directional Antenna the transmitting antenna puts out a focused electromagnetic beam the transmitting and receiving antennas must be aligned

Dr. Yagi and his Yagi antenna (example of directional antenna)

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Omnidirectional Antenna the transmitted signal spreads out in all directions and can be received by many antennas

In general, the higher the frequency of a signal, the more it is possible to focus it into a directional beam

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Microwave Frequencies in the range of about 30 MHz to 40 GHz are referred to as microwave frequencies 2 GHz to 40 GHz ◦ wavelength in air is 0.75cm to 15cm ◦ wavelength = velocity / frequency

◦ highly directional beams are possible ◦ suitable for point-to-point transmission

30 MHz to 1 GHz ◦ suitable for omnidirectional applications

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Terrestrial Microwave Limited to line-of-sight (LOS) transmission ◦ This means that microwaves must be transmitted in a straight line and that no obstructions can exists, such as buildings or mountains, between microwave stations.

To avoid possible obstructions, microwave antennas often are positioned on the tops of buildings, towers, or mountains

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Applications Long-distance telecommunication service ◦ requires fewer amplifiers or repeaters than coaxial cable ◦ requires line-of-sight transmission ◦ Example ◦ telephone system ◦ TV distribution

Short point-to-point links ◦ Data link between local area network ◦ closed-circuit TV

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Another apps: cellular communication, and LANs Freq. Band 824 - 894 MHz 902-928 MHz 1.7 - 2.3 GHz 1.8 GHz 2.400-2.484 GHz 2.4 GHz 2.45 GHz 4 - 6 GHz Infrared

Use Analog cell phones (AMPS) License free in North America PCS digital cell phones GSM digital cell phones global license free band 802.11, Lucent WaveLAN Bluetooth commercial (telecomm.) short distance line of sight

Range Data Rate 20 km per cell 13 kbps/channel < 1 km per cell 16 kbps/channel 100 m - 25 km about 10 m 40 - 80 km 5 - 100 m

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2 - 11 Mbps 1 Mbps 100 Mbps 1 Mbps

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Transmission characteristics The higher the frequency used, the higher the potential bandwidth and therefore the higher the potential data rate Band (GHz)

Bandwidth (MHz)

Data rate (Mbps)

2

7

12

6

30

90

11

40

90

18

220

274

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Satellite Microwave

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a satellite is a microwave relay station ◦ link two or more ground-based microwave transmitter/receivers (known as earth stations or ground stations)

The satellite receives transmissions on one frequency band (uplink), amplifies or repeats the signal, and transmits it on another frequency (downlink) ◦ An orbiting satellite operate on a number of frequency bands, called transponder channels

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Geostationary Satellites It is launched into an orbit above the equator at 35786 km ◦ This orbit distance means that the satellite is orbiting the earth as fast as the earth is rotating. ◦ It appears to earth stations that the satellite is stationary, thus making communications more reliable and predictable ◦ Earth stations is less expensive because they can use fixed antennas

Delay is 250 -500ms for geostationary satellites Apps: television broadcasting and weather forecasting, and have a number of important defense and intelligence applications, VSAT

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VSAT A Very Small Aperture Terminal (VSAT), is a two-way satellite ground station with a dish antenna that is smaller than 3 meters. Most VSAT antennas range from 75 cm to 1.2 m.

Data rates typically range from 56 Kbit/s up to 4 Mbit/s VSATs access satellites in geosynchronous (geostationary) orbit (to relay data from small remote earth stations (terminals) to other terminals (in mesh configurations) or master earth station "hubs" (in star configurations).

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Low earth orbit (LEO) and Medium earth orbit (MEO) satellites For small mobile personal communications terminals, a network with significantly reduced transmission and processing delay is required

Such a service could be provided by low earth orbit (LEO) and medium earth orbit (MEO) satellite systems These systems can provide direct personal-terminal-to-personalterminal connectivity (satellite phone services)

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LEO A Low Earth Orbit (LEO) typically is a circular orbit about 400 kilometers above the earth’s surface and, correspondingly, a period (time to revolve around the earth) of about 90 minutes One of apps: to provide satellite phone services, primarily to remote areas

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MEO Medium Earth orbit (MEO), sometimes called intermediate circular orbit (ICO), is the region of space around the Earth above low Earth orbit (altitude of 2,000 kilometers (1,243 mi)) and below geostationary orbit (altitude of 35,786 kilometers (22,236 mi)) The most common use for satellites in this region is for navigation, such as the GPS

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Frequency allocation Optimum frequency range for satellite transmission is 1 - 10GHz

Below 1 GHz, there is significant noise from nature sources About 10 GHz, the signal is severely attenuated by atmosphere

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Broadcast Radio

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Physical description ◦ omnidirectional

Applications ◦ AM broadcasting ◦ Operating frequencies ◦ MF (medium frequency): 300 kHz - 3 MHz ◦ HF (high frequency): 3 MHz - 30 MHz ◦ HF is the most economic means of low information rate transmission over long distances (e.g. > 300km)

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A HF wave emitted from an antenna is characterized by a groundwave and a skywave components. The groundwave follows the surface of the earth and can provide useful communication over salt water up to 1000km and over land for some 40km to 160km The skywave transmission depends on ionospheric refraction. ◦ Transmitted radio waves hitting the ionosphere are bent or refracted. ◦ When they are bent sufficiently, the waves are returned to earth at a distant location. ◦ Skywave links can be from 160km to 12800km.

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FM broadcasting operating frequencies ◦ VHF (very high frequency): 30 MHz - 300 MHz TV broadcasting ◦ operating frequencies: ◦ VHF ◦ UHF (ultra high frequency): 300 MHz - 3000MHz

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Infrared 1. Does not penetrate walls ◦ no security or interference problems 2. No frequency allocation issue ◦ no licensing is required 3. Apps: Infrared Wireless LAN

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So..you’ve heard about dB.. What is it?

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Decibel, Gain, dan Loss Power loss : penurunan daya sinyal Power gain : penguatan daya sinyal Decibel : “satuan” untuk menyatakan power loss/gain ◦ Decibel merupakan satuan ukuran daya yang logaritmis ◦ Pertama kali digunakan oleh Alexander Graham Bell (satuan decibel digunakan untuk menghormati jasanya) ◦ Decibel : dB

Alexander Graham Bell Born 1847 - Died 1922

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Decibel in Action

Gain g = Pout/Pin

Overall Gain g = g1*g2

Gain in dB gdB = 10 log (Pout/Pin)

Overall Gain in dB gdB = g1(dB) + g2(dB)

Loss L = Pin/Pout Loss in dB LdB = 10 log (Pin/Pout)

Contoh: - Bila daya output 10 Watt dan daya input 1 Watt, maka Gain = 10 dB - Bila daya input 10 Watt dan daya output 1 Watt, maka Loss = 10 dB (atau Gain = -10 dB)

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Rumus dB menyatakan ukuran daya Jika kita lebih tertarik akan perubahan pada tegangan maka faktor impedansi harus dimasukkan pada perhitungan dB

g dB

 Zin   Pout   Vout     20 log    10 log   10 log   Pin   Vin   Zout 

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Power Levels in dB Sampai titik ini kita masih melihat penerapan dB untuk menyatakan perbandingan daya Bagaimana cara menyatakan level daya absolut menggunakan dB?

Gunakan suatu daya referensi

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Daya referensi yang banyak digunakan adalah 1 mW Satuan dB yang dihasilkan adalah dBm Contoh: suatu level daya 10 mW bila dinyatakan di dalam dB adalah 10 dBm Daya referensi lain yang dapat digunakan: 1 Watt (satuan dB yang digunakan dBW)

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 P  PdBm  10 log    1 mW   P  PdBW  10 log    1W 

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Satuan lain yang biasa digunakan untuk menyatakan suatu perbadingan adalah Neper 1 Neper (Np) = 8,685889638 dB 1 dB = 0,115129254 Np

John Napier or Neper nicknamed Marvellous Merchiston (1550, 1617) Penemu Logaritma

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