Telecommunication

1
Telecommunication

• How It works

2
What It is?

• Telecommunication, devices and systems that
  transmit electronic or optical signals across
  long distances. such as a telephone system.
• enables people to send and receive personal
  messages .
• key medium for delivering news, data,
  information, and entertainment.

3
Way of sending Message

• Point-to-point One sender to a single receiver
  such as telephone conversation
• Point-to multi point one sender to many
  receiver such as television, It often called
  Broadcast

4
How the signals sent?

• Telecommunications devices convert different
  types of information, such as sound and video,
  into electronic or optical signals.
• Electronic signals travel along a medium such as
  copper wire or are carried over the air as radio
  waves. Optical signals travel along optical fiber
  cable
• the device on the receiving end converts the
  signal back into an understandable message, such
  as words and pictures on a computer screen.

5
Types of signal

• analog or digital refers to the method used to
  convert information into an electrical signal

• Analog signal
• Digital signal
• Optical signal

6
Analog signal

• An analog signal is any continuously variable
  signal
• in an analog sound recording, the variation in
  pressure of a sound striking a microphone creates
  a corresponding variation in the current passing
  through it. An increase in the volume of the
  sound causes the fluctuation of the current to
  increase

7
Digital signal

• 0 volt means 0
• 5 volts means 1

8
Optical signal

• Pulse beam of laser light
• LED (Light Emitting Diode) send signal
• Fiber optic receiver Receive fiber optic signals

9
Transmission medium

• Cable
• Fiber-optic
• Micro-wave
• Satellite

10
Coaxial cable

• Developed in 1936
• Made of copper wire
• Expensive

11
Fiber Optics

• Message are digitally coded into pulses of light
• TAT 9 fiber optic cable can carry more than
  75,000 telephone conversation at a time

12
Microwave relay

• Relay from station to station
• Needs a clear line of sight between sending and
  receiving station
• Average distance between stations 40km
• As many as 600 telephone conversations can be
  transmitted over one microwave relay channel.

13
Satellite communication

• Started at 1969 with series of satellites
• Orbit 35,880km above the earth
• Powered by solar energy
• Use micro wave for transmission
• can relay up to 33,000 calls simultaneously as
  well as several television channels.

14
Way of transmission

• Simplex One way communication
• Half Duplex communications in both directions,
  but only one direction at a time
• Duplex communication in both directions
  simultaneously

15
Applications

• Telegraph
• Fax
• Telephone
• Radio
• Television
• Global Positioning System
• Voice Over IP

16
Computer network
17
Telephone cellular Communication
18
Global Positioning System

• space-based radio-navigation system consisting of
  24 satellites and ground support.
• accurate information about their position, time,
  anywhere in the world and in all weather
  conditions.

19
How GPS Works

• GPS satellites fly in circular orbits at an
  altitude of 20,100 km (12,500 mi) and with a
  period of 12 hours
• point their solar panels toward the sun and their
  antennas toward the earth
• Send the signals to the receiver
• From that signal receiver calculate its position
  on earth

20
Application of GPS

• Military equipment such as fighters, bombers,
  tankers, helicopters, ships, submarines, tanks,
  jeeps, and soldiers
• Airplane and ships use it for route navigation
• used to route and monitor delivery vans and
  emergency vehicles
• car navigation system
• Because the GPS user does not need to communicate
  with the satellite, GPS can serve an unlimited
  number of users.

21
Inventor

• In 1837 Samuel Morse invented the first workable
  telegraph
• Alexander Graham Bell invented telephone in 1876
• Marconi invented Radio in 1895