COMMUNICATION SYSTEM NEW TOPICS:
INTERNET: It is a global network of computers
which provides facilities to exchange all kinds of information amongst users
connected to this network.
Applications: 1. E-mail: Electronic mail is a way of
sending text, images, videos or stored files on computer through internet. It
is fastest, cheapest paperless mode of sending messages.
2.
E-shopping/commerce: we can view different products on virtual shops on net and
place order for purchase.
3.
E-banking-booking (rail &flight tickets, hotels booking), social networking
(Facebook, Twitter, Google+,Etc.)
MOBILE TELEPHONEY: A device which can send
and receive signals of frequencies 800-950 MHz without using any wire connections.
It is based on cellular radio network technology, in this network a given
physical area is divided into smaller parts called cells or cell zones. In
every cell an Antenna is installed to receive and send signals to all mobile
phone located in that cell. Handling of all outgoing and incoming calls is
managed through Mobile Telephone Switching Office (MTSO).
Working:
When any person dial mobile number or telephone number, then an electromagnetic
signals of certain frequencies are generated .which is transmitted to antenna
of cell, in which the mobile is located. The cell antenna transfers this
signals to MTSO. Which locates the mobile to be connected .exactly the same
process takes place, when the person on other side. Whole process completes in
few seconds.
Note:(SIM-subscriber
identity module).
GPS (Global Positioning System): It is a method of
locating position of any person or place on earth by using electromagnetic
waves and satellite system. It uses a set of 24 satellites, which are
continuously orbiting and mapping the earth surface .the orbits of these
satellite revolving around the earth twice a day, are so adjusted that at least
four of these always keep looking any place on the surface of earth.
Applications: 1. Map designing of a location.
2.
Keeping standard time world over.
3.
Help in navigation on land, water or air.
4.
Tracking of animals, birds, plants etc.
5.
Measurement of speed of moving objects.
