hi guys in today's video we are going to
study about transmission media
before proceeding to the lesson let's
have a look at the learning outcome
in this chapter we will learn about
physical connections
the guided media and wireless
connections
the unguided media
transmission media is communication
channel
that is used to carry the data from the
transmitter to the receiver
through the electromagnetic signals or
in other words
transmission media carries data from one
computer to another
these signals are transmitted from one
device to another
in the form of electromagnetic energy
electromagnetic energy is a combination
of electrical and magnetic field
vibrating in relation to each other
electromagnetic signals
can travel through a vacuum air or other
transmission media
for example power voice radio waves
infrared light visible light ultraviolet
light
gamma and cosmic rays the main
function of this is to carry the data in
the bits form
through the local area network in data
communication
it works like a physical path between
the sender
and the receiver for instance in a
copper cable network
the bits in the form of electrical
signals whereas
in a fiber network the bits are
available in the form of
light pulses the quality as well as the
characteristics of data transmission
can be determined from the
characteristics of medium
and signal the properties of different
transmission media
are delay bandwidth maintenance
cost and easy installation
some factors need to be considered for
designing the transmission media
firstly it is about bandwidth all the
factors are remaining constant
the greater the bandwidth of a medium
the higher the data transmission rate of
a signal secondly is transmission
impairment
it is when the received signal is not
identical to the transmitted one
due to the transmission impairment the
quality of the signal will get
destroyed
due to the transmission impairment
thirdly it is about interference
and interference is defined as the
process of disrupting a signal
when it travels over a communication
media on the addition of some unwanted
signal
now let's look at the causes of
transmission
impairment firstly
it is about attenuation attenuation
means the loss of energy
for example the strength of the signal
decreases with
increasing the distance which causes the
loss of energy
secondly distortion distortion occurs
when there is a change in the shape of
the signal
this type of distortion is examined from
different signals
having different frequencies each
frequency component has its own
propagation speed
so they reach at a different time which
leads to the delay distortion
thirdly it is about noise when the data
is traveled over
transmission medium some unwanted signal
is added to it
which creates the noise
there are two categories of
communication channels
firstly it is physical connections the
guided media
secondly wireless connections the
unguided media
physical connection is referred to as
wired or bounded transmission media
signals being transmitted are directed
and confined in a narrow pathway by
using physical
links there are three types of
physical connections they are twisted
pair
coaxial cable and fiber optic cable
twisted pair is a physical media made up
of a pair of cables
twisted with each other twisting reduces
interference crosstalk from electrical
signals
a twisted pair cable is cheap as
compared to other transmission media
installation of the twisted cable is
also
easy and it is a lightweight cable
now let's look at coaxial cable
this cable contains an external plastic
cover
and it includes two parallel conductors
where each conductor
includes a separate protection cover
this cable is used to transmit data
in two modes like baseband mode as well
as the broadband mode
this cable is widely used in cable tvs
and analog tv networks by using this
cable
the data can be transmitted at high
speed
secondly it has better shielding as
compared to twisted pair cable
thirdly it provides higher bandwidth
the disadvantages of this cable is
it is more expensive as compared to
twisted pair cable
next if any fault occurs in the cable
causes the failure in the entire network
a fiber optic cable is dozens or
hundreds of
thin strands of glass or plastic that
transmit
pulses of light not electricity
it is used for transmission of large
volumes of data a fiber optic cable
has lower error rate and more expensive
than
twisted pair or coaxial cable it is also
lighter and more durable than twisted
pair or coaxial cable
this picture shows a fiber optic cable
following are the advantages of fiber
optic cable
over copper firstly the fiber optic
cable provides more bandwidth
as compared copper therefore the fiber
optic carries more data
as compared to copper cable secondly
fiber optic cable carries the data in
the form of light
this allows the fiber optic cable to
carry the signals at a higher speed
thirdly the fiber optic cable carries
the data at the longer distance
as compared to copper cable next
the fiber optic cable is more reliable
than the copper cable
as it is immune to any temperature
changes
while it can cause obstruct in the
connectivity of copper cable
lastly it is thinner and sturdier
a fiber optic cable is thinner and
lighter in weight
so it can withstand more pull pressure
than
copper cable
the disadvantages of fiber optic cable
are difficult to install and maintain
high cost and fragile
now let's move on to wireless
connections the unguided media
it doesn't require any physical medium
to transmit electromagnetic signals
electromagnetic spectrum of radiation is
the basis of
all telecommunication signals wired and
wireless
radio-frequency spectrum is the part of
the electromagnetic spectrum
that carries most communication signals
signals are broadcast through air or
water
and thus available to anyone who has a
device
capable of receiving them the main
features of this media are
less secure the signals can be
transmitted through air
and applicable for large distances
there are three types of unguided media
firstly let's look at radio waves
radio waves are the electromagnetic
waves that are transmitted in all the
directions of free space
radio frequency spectrum is the part of
the electromagnetic spectrum
that carries most communication signals
a radio wave is useful for multi-casting
when there is one
sender and many receivers an example of
the radio wave is
am or fm radio cell phones and police
radio
a radio wave sends data over long
distances
using a transmitter and a receiver
the advantages of radio waves are it is
mainly used for
wide area networks and mobile cellular
phones
secondly it covers a large area and they
can penetrate the walls
thirdly it provides a higher
transmission rate
the second unguided media is microwaves
microwaves are radio waves that provide
a high speed signal transmission
they do not follow the curvature of the
earth
it is a line of sight transmission for
example
the sending and receiving antennas need
to be properly aligned with each other
the distance covered by the signal is
directly proportional to the height of
the antenna
these are majorly used for mobile phone
communication
and television distribution
there are two types of microwaves
firstly
it is terrestrial microwave and secondly
satellite microwave communication
the advantages of using microwaves are
microwave transmission is cheaper than
using cables
secondly it is free from land
acquisition
as it does not require any land for the
installation of cables
thirdly the communication over oceans
can be achieved
by using microwave transmission the
disadvantages of microwave transmission
are firstly it is about eavesdropping
an eavesdropping creates insecure
communication
any malicious user can catch the signal
in the air
by using its own antenna secondly
a signal can be moved out of phase by
using microwave transmission
thirdly a microwave transmission is
susceptible to weather condition
this means that any environmental change
such as rain
wind can distort the signal lastly
allocation of bandwidth is limited in
the case of microwave transmission
infrared waves are used in extremely
small distance communication
as they cannot go through obstacles so
it stops intrusion
between systems these waves are used in
tv remotes
keyboards wireless mouse printer and etc
well that's all for this chapter thank
you so much for
watching hope you all could understand
today's lesson
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thank you so much see you all in next video bye
