presentation of Guided and unguided media presented at Usman Institute of technolgy

1. Guided& Unguided
Media
Presented
BY
Ali Akbar Channa
Mir Osama Sultan
Maryam Ashfaque
Noor-ul-Huda

2. Introduction
Transmission medium is the physical path between Transmitterand Receiverin a data
transmission system.Transmission media can be classified as Guided or Unguided. In both
cases, communication is in the form of electromagnetic waves.
With guided media, the waves are guided along a solid medium, in Unguided without the need
for any physical medium even through a vacuum.
Transmission media are located below the physical layer
Computers use signals to represent data.
Signals are transmitted in form of electromagnetic energy.
sender
Receiver
Sender Receiver

3. Key Factors inTransmission Media
Data Rate & Bandwidth
Higher Bandwidth gives
higher data rate :
Capacity (Bandwidth andThroughput):
Interference
Cost & Ease of
Installation
Delay Distortion
Attenuation
Intermodulation Interference/Cross-
Talk/Impulse Noise:

4. Guided Media
The electromagnetic signals travel between the communicating devices through a physical
medium/conductor. it also provides Directionto the signal having some limitation of the
Conductor
 length of the conductor
 installation cost
 maintenance, etc.
Guided
Media(Wired)
Twisted-
Pair Cable
Coaxial
Cable
Fiber-Optic
Cable

5. A twisted pair cable is made ofTwo plastic insulated copper wires twisted together to
form a Single Media that is bundled together in a protective sheath. One of the wire
carries signal other for ground reference,
mainly used for short to medium range network connections for residential and
business-based Local Area Networks
formerly used for telephone
Early internet networks
Characteristic
s
Analog
needs amplifiers every 5km to 6km
Digital
 can use either analog or digital signals
 needs a repeater every 2-3km
 limited distance
 limited bandwidth (1MHz)
 limited data rate (100MHz)
 susceptible to interference and
noise

6. Two-Types of Twisted-Pair Cable
Unshielded-Twisted Pair Shielded-Twisted Pair
Unshielded-Twisted Pair
UTP cables do not possess any type of
shielding to protect against signal
distortion/interference
∏ Ordinary telephone wire
∏ Cheapest , Easiest to install
∏ Suffers from external
EM interference
ꬸ Shielded-TwistedPair
STP cables have special metallic mesh
shielding that protects against noise
and cross-talk
Ώ Metal braid or sheathing that
reduces interference
Ώ More expensive
Ώ Harder to handle (thick, heavy)

8. The coaxial cable is a popular wire used for Audio and Visual purposes, especially Televisions and
VCRs. It isn’t perfect, but the fact it is compatible with so many products makes it the best cable of
its type on the electronic market. Users should understand how the coaxial cable works before
installing it.
Merits & Demerits

10. A fiber optic cable is a Network cable that contains strands of glass fibers
inside an insulated casing.They're designed for long distance, very high-
performance Data Networking, and telecommunications.
They consist of One or More strands of glass, each only slightly Thicker than a
strand of Human Hair
Compared to wired cables, fiber optic cables provide Higher Bandwidth and can
transmit data over longer distances. Fiber optic cables support much of the
World's Internet, CableTelevision and TelephoneSystems

12. 1. Single-Mode Optic Fibers:
2. Multi-Mode OpticFibers:
(i) Stepped-Index:
(ii)Graded-Index:
Transmits only one mode or wavelength of around 1310nm-1550nm across the length of a cable. Feature
speeds of upto 10 Gbps with more bandwidth and less disruption as compared to mutli-mode optic fibers.
Used for long distance communications between countries or continents.
Transmit multiple modes of light around a wavelength of 850nm to 1300nm using total internal reflection of
light. Experience more disruptions (along with lower bandwidth) due to presence of modes that do no
experience total internal reflection and are ‘lost’.
The refractive index of the core is uniform throughout the cable causes some of the light rays that comprise a
digital pulse to travel a direct route while the others “bounce” off the cladding and arrive separately at the
receiving point, causing signal disruption. Best suited for short distance communication.
The refractive index of the core changes gradually from the center towards its cladding., wiith a higher index
at the center decreasing outwards. Due to this graded index, light travels helically rather than zigzagging,
reducing its travel distance and disruption. Best suited for LAN connections.

14. Unguided Media

15. Line of sight (LoS) is a type of propagation that canTransmit and Receive data only
where transmit and receive stations are inView of each other without any sort of an
Obstacle between them. FM Radio, Microwave and Satellite transmission are examples
of line-of-sight communication.
Sky Propagation: Higher-frequency signal waves radiate upward into the
ionosphere (60-1,100 km above the Earth) where they are reflected back to
Earth. This type of transmission allows for very long distances, even
trans-continental, transmissions
Ground Propagation: Signal waves travel through the Lowest Portion of the
atmosphere, “Hugging” the Earth.These Low-Frequency signals emanate in all
directions from theTransmitting Antenna and follow the Curvature of the planet over a
long distance.
Three ways of transmitted from a source to destination:
 Ground Propagation
 Sky Propagation:
 Line-of-sight Propagation:
Unguided Media

16. Electromagnetic waves ranging in frequencies between 3 KHz and 300 GHz and wavelengths between 1mm and
100km are normally called RadioWaves, Radio waves are Omnidirectional, meaning that when a Radio Antenna
Transmits radio waves they Travel in all directions from the source
so that both sending and ReceivingAntennas do not need to be aligned properly.
3 forms of wave propagation:
 Low-Frequency (LF) Radio waves through ground propagation,
 Medium Frequency (MF) Radio waves through sky propagation (albeit very unreliable)
 High-frequency (HF ) radio waves through line-of-sight propagation.

17. Electromagnetic waves ranging in frequencies between 300 MHz and 300 GHz and wavelengths
between 1mm and 1m are normally called Microwaves. High-frequency microwaves are unable to penetrate
buildings and they are Unidirectional,
Two types of antennas:
 Parabolic Dish Antennas
 Horn Antennas
A parabolic antenna works as a funnel, catching a wide range of waves and directing them to a common
point, recovering more of the signals than would be possible with a single-point receiver
A horn antenna looks like a gigantic scoop.it is Consist of flaring metal waveguide shaped like Horn to direct radio
waves in a Beam. Horns are widely used as Antennas at UHF and Microwave frequencies

19. InfraredWaves
Electromagnetic waves ranging in frequencies between 300 GHz and 300THz and wavelengths between
700nm and 1mm (between microwaves and the visible light spectrum) are normally called
infrared waves.
Advantages
• Point-to-Point
• Line of Sight
• Portable
• Transfer data up to 1m
• Low power Consumption
• Inexpensive
Disadvantages
• one device at aTime
• Limited no: of free frequency Band
• Limited Spectrum of frequency
• Low Bandwidth characteristic
• Low Capacity

20. Any Query?