Satellite communication system uses satellite technology for
communications. The services provided by satellite communications are
internet, voice and video calling, fax, radio channels, military
applications and television.
In satellite
communication, transferring of signal between the receiver and sender
is done with the help of satellite. The signal is a beam of modulated
microwaves sent towards the satellite. Then the signal is amplified
by satellite and sent back to the antenna of the receiver present on
the earth’s surface.This type of communication is called space
communication.
Satellite communications
can provide communication capabilities spanning long distances and
can operate under conditions which are inoperable for other forms of
communication.There are around 2,000 communications satellites
present in Earth’s orbit, used by both government and private
organizations.
Two types of satellites
which are used commonly in satellite communication are active and
passive satellites:-
Passive satellites:
It is like a plastic balloon with a metal coated over it. This sphere
reflects the microwave signals coming from one location of the earth
to another one. This is also called passive sphere. Moon is passive
satellite of the earth.
Active satellites:
It basically amplifies the microwave signals coming. In active
satellites a receiver, an antenna system, power supply, transmitter
is used. These satellites are also called as transponders. Microwaves
are generated by the transmitters fitted on the earth.
These rays are then
received by the transponders attached to the satellite. After
amplifying, these signals are then transmitted back to earth. This
sending can be done at the same time or after some delay. These
amplified signals are later stored in the memory of the satellites,
when earth faces the satellite. Afterwards satellite sends the
signals to earth.
Some active satellites
also have recording and programming features. Then these recordings
can be easily watched. The signals that come from the satellite are
of very low intensity. Their receivers then amplify these signals
themselves. After amplification they become available for further
use.
