Transmission Media

Presented BY SURAJ PATEL N.M.F. College F.Y.Bsc.IT

Contents : -• Introduction• Factor Affecting Data Communication Media• Reasons For Transmission Impairence• Types Of Transmission Media 1- Wired or Guided Media Twisted Pair Wire Co-axial Cable Optic Fibre 2- Wireless or Unguided Media Radio Wave Microwave Infrared• Conclusion

Introduction :-

• Transmission Of Data Through Medium

Is Called As Transmission Media.

• A Transmission Medium Can Be Defined As

Anything That Can Carry Information For A

Source To A Destination.

• The Transmission Medium Usually A Free Space,

Metallic Cable , Or Fibre-Optic Cable.

• Mainly Two Types Of Transmission Media

Wired Media

Wireless Media

• Signals Are Transmitted In The form of electromagnetic

Energy.

Factor Affecting Data Communication Media :-• Communication Bandwidth Of The Medium

• Interference

• The Transmission Impairments

• The Bandwidth Of A Medium Determines The Signal frequencies That Can Be Carried In The Medium.

• A Wide Bandwidth, Or Broadband, Usually Allows Communication At A Higher Data Rate.

Reasons For Transmission Impairence :-• Attenuation: - The Loss of a Signal’s Energy When the Signal Is Transmitted across a Medium.

• Distortion During Signal Propagation: - The Distortion On The Signal In Transmission Due To Unwanted Signals From Outside Sources.

• Noises: - Random Signals That Can Be Picked Up During Signal Transmission And Result In Degradation Or Distortion Of Data.

• Bandwidth: The Difference between the Lowest and Highest Frequency Signals That Can Be Transmitted Across a Transmission Line or Communication System

Guided Transmission 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.• Transmission Capacity Depends On The Distance And On Whether The Medium Is Point-to-Point or Multipoint.• Guided Media Provide A Physical Path Along Which The Signals Are Propagated

Guided Media

Twisted Pair Co-Axial Cables Optic fibers

Types Of Twisted Pair :

1-Twisted-Pair Wires :-• Consisting of pairs of twisted copper wires Arranged in a

regular spiral pattern to minimize the electromagnetic

Interference between adjacent pairs.

• Low frequency transmission medium.

• Mainly Used To Transmitt Analog Signal , Also Transmitte Digital Signal.

• Twisted Pair Is Limited In Distance, Band Width and Data Rate.

Unshielded Twisted Pair :-

Ordinary Telephone Wire, Cheapest.

Easiest To Install.

Shielded Twisted Pair :-

Metal Braid or Sheathing That Reduces Interference

More Expensive

Harder To Handle (Thick, Heavy)

Advantages :-Inexpensive And Readily Available.

Flexible And Light Weight.

Disadvantage :-

Susceptibility To Interference And Noise.

Relatively Low Band Width.

Application :-Used In Telephone Lines To Provide Voice &

Data Channel.

Co-axial Cable (or Coax) :-• Coaxial Cable Consists Of A Core Made Of Solid Copper Surrounded By Insulation, A Braided Metal Shielding, And An Outer Cover.• Inner conductor is a solid wire outer conductor serves both as a shield.• Outer Packet of Tough Jacket.

Advantages:- Higher Bandwidth( 400 To 600 MHz) Much Less Susceptible To Interference than Twisted Pair.Disadvantages:- Bulky High Attenuation Rate Make It Expensive Over Long Distance.Application:- Used In Television Distribution- Cable TV Network. Traditional Ethernet LANs. Can Carry 10,000 Voice Call Simultaneously. Traditional Ethernet LAN – 10Base2, 10Base5.

Optical Fibre :-• A Fiber-Optic Cable Is Made Of Glass or Plastic And Transmitte Signals In The Form Of Light.

• Core Is of Glass or Plastic Is Surrounded by Cladding .Cladding Is of Less Dense Glass or Plastic.

• Bending Of Light Ray.

Transmission Modes :-

Optical Fibre :-Advantages :- Greater Capacity (Bandwidth Up TO 2 Gbps) Small Size And Lighter Weight.

Lower Attenuation

Electromagnetic Isolation

Disadvantages :- Expensive Over Short Distance.

Requires Highly Skilled Installer.

Adding Additional Nodes Is Difficult.Application :- LAN -100 BASE FX- Network (Fast Ethernet),

Cable-TV Backbone, Backbone Network-SONET.

Unguided Transmission Media : -• Transmission And Reception Are Achieved By Means of An Antenna.• Unguided Media Transport Electromagnetic Waves Without Using A Physical Conductor.• Signals Are Normally Broadcast Through Free Space And Thus Are Available To Anyone Who Has A Device Capable Of Receiving Them.• Wireless Example. Microwave , Radio Wave , Infrared Wave.

Propagation Methods :-

Omnidirectional Antenna : -

Radio Waves : -• Radio Wave Particularly Those Wave That Propagate In

The Sky Mode, Can Travel Long Distances.

• Encompass Frequency In The Range 3 KHz To 300 GHz.• Radio Wave Is Omnidirectional.

• Still Need Line Of Sight.

• Suffers From Multipath Interference Reflection for Land, Water, Other Object.

Frequency Between 3KHz To 1 GHz.

Are Used For Multicasts Communication Such As, Radio and

Television And Paging System.

Uses & Application: -

• Use Broadcast Radio 30 MHz To 1GHz , For FM Radio ,UHF And VHF Television

• useful for multicasting, in which there is one sender but many receivers.

• AM and FM Radio, television, maritime radio, cordless phone, and paging are examples of multicasting .

Unidirectional Antenna :-1-Parabolic Dish2-Hom

Microwave : -• Electromagnetic Waves Having Frequency Between 1 and 300 GHz.• Microwaves Are Unidirectional.

• Microwave Propagation Is Line- Of –Sight.

• Very High Frequency Microwaves Can Not Penetrate Walls.

• The microwave band is relatively wide, almost 299 GHz.

Two Types of Microwave:-

Terrestrial Microwave Satellite Microwave

Send For Long-Haul Communication. A Microwave Relay Station in Space.

1-40GHz Frequency. Geo-Stationary Satellite:

Higher Frequency Gives Higher Data Rate. Height of 35,784 Km.

Use A Parabolic Dish for Transmitter. Travel around the Earth Rotation

Uses & Application :-• They Are Used In Cellular Phones, Wireless LAN’s And Satellite Network.

• Private Business

• Global Positioning.

Infrared : -• With Frequency from 300 GHz to 400 THz (1 nm to 770 nm).• Can Not Penetrate Walls Having High Frequency.• No Licences Required.• Used For Short – Range Communication• We cannot use Infrared waves outside a building because the sun rays Contain Infrared waves that can interfere with communication.

Application & Uses : -• Infrared waves are used in communication between devices such as Keyboard, PCs and Printers.• Home Security System.• TV Remote Control.

The End …..

Conclusion :- In Summary, Transmission Media Are Essential For Communication Systems. Signals That Carry

Information Can Be Transmitted In A Transmission Medium For Communication Purposes.

The Transmission Characteristics of The Medium In Use Are Important Because They Directly Affect The

Communication Quality. Since Different Types of Transmission Media Have Different Transmission

Characteristics And Costs. They Are Used In Different (And The Most Suited) Applications.