Communication for 3ESO students

1. Communication
technologies
Technology 3 ESO

2. Index
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What is communication?
What are the main components of communication
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What kinds of communication technologies exist?
Communication signals
Guided communication
Non guided communication: electromagnetic
space
Telephone: Conmutation and mobile phones
Radio
Television
GPS
Internet

3. What is communication?
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Communication is a proccess in which two
or more agents interchange information
Index

4. Elements of Communnication
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Emisor, who produces the message and sends it
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Receiver: who receives the message
(emisor and receiver often interchange roles during
the communiaction proccess)
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Message: information sent from one to another
Channel: The form of interchanging information.
i.e: radio, press, TV, telephony…
Medium: the physical which information flows
through. i.e: paper, space, wires…
Index

5. Classification of communication
Technologies
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Communication
technologies are often
classiffy according to
the medium in:
Guided: They use a
material medium such
as electric wires,
optical fiber
Non guided: the
information is carried
in waves thoruogh the
space
Index

6. Communication signals
Communication sisgnals can be:
 Analogic: Which can have whatever
value in a range
 Digital: which are coded binary and
can be proccessed by a computer.
Index

7. Guided communication
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In guided communication,
information flows thorough
material elements: electric
wires, optical fibre
Before being send,
communication is transformed
into electric or optic signals.
Electric wires: Much cheaper but
suffers from interference and
atenuation (the signal weakens
with distance). i.e: telephony,
Optic fibre: much more
expensive and delecated but
doesn’t suffer from interferences
or atenuation: ADSL, digital TV
Index

8. Non guided communication
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In non guided communication,
communication flows through
the space in the form of
electromagnetic waves.
Radioelectric space
(spectrum) is the whole range
of frequencies or wavelengths
of electromagnetic waves: it
is divided in different regions:
gamma, X, ultarviolet, visible,
infrared, microwave and
Radiofrecuencies (RF): the
most usual communications
use from IR to RF
Terrestrial anthens and
satellites are used to send,
repeat and receive
information.
Index

9. Telephony
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Telephony consists of interchanging
acustic signals beetween an emisor and a
receptor who interchange their roles.
There are two kinds of telephony :
Conmuted grid: telephones terminals are
connected to a guided grid. A node system
provides a guided way to connect the two
terminals in communication.
Mobile phones are connected by satellites
which receive their signals and sends them
signals from other terminals. They can
also connect to the conmuted grid
through speciphic devices. Last generation
mobiles have turned into small/powerful
multifunction devices with a powerful
microproccessor inside
Index

10. Radio
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In radio, sound signals
flow in form of waves
from an emisor to a
receiver, both having
anthens.
Radio has only one
direction, the emisor
and the receiver do
not interchange their
roles
Index

11. Television
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In television, audio and images are sent from an
emisor to a receiver in the form of waves
(anthens) or by a wire (TDT).
There are different technologies to produce
Index
images in an screen_(plasma, RCV, LCD)

12. GPS (Global positioning system)
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GPS was invented by the
USA’s army
A GPS uses a system of 8
or more satellites and a
terrestrial receiver.
The receiver and at least
three satellites interchange
signals. The time it takes
to the signal to trip
between them gives the
receiver know the
distance. Taking three
signals of distance at the
same time, the receiver
works out its position in
the earth’s surface.
Index

13. Internet
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Internet is a worldwide system of
interconected computers which
interchange information. There are
different ways of connecting to the
internet (transmmision protocols)
TCP-IP: Where information is divided
into small packages (TCP) and sent
from a server (computer) to a client
computer.
P2P (peer to peer), where it doesn’t
exist a client-server jerarchy.
Computers share their hardware
resources acting as servers or clients
at the same time.
Several devices are used to connect to
the internet: modems, routers. Todays
computers, PDA’s provide their on
anthen to connect via wi-fi
A specific software (explorers) are
used to interchange information.
Internet provides many different
utilitis such as e-mail, information
(web pages), news, telephony,
videoconferences, virtual market, etc
Index