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The wired transmissionconsist of the use of a physical
support for transmission. It is used when you need a high
quality of transmission or when the environmental accidents
or the weather are extreme, makes more difficult the
transmission of electromagnetic waves. One of the first
supports as used was wire cable.
It is a copper wire, protected by an insulating
Transmitting the converted electromagnetic
into electrical current, or a series of specific
Often used in wireline systems
-This cable is a moderately immne to outside
electromagnetic interference compared to
-It is also well suited for broadband applications.
-Expensible and inflesible
Optic fibre cable:
-Has much grta transmission than the other tipes
-It is inmmune to outside interferences.
-It is used in the higher rate communications
The routing of signals is based on the transmission of light signals
through a canal inside which the total reflection occurs.
Inside the core of the fibre are transmitted beams of light that are
reflected and continue extending.
USE OPTICAL FIBER
The core formed by high transparency
materials so that losses are lower.
Possibility of sending of a same fiber up to 100
light beams and high speeds are achieved
Fiberglass is fragile and difficult to repair,
connections with it are difficult and is a
expensive than other cable
The signals in the form of light must also
become electrical signals to be used by
devices that are connected through optical
Is applied in the field of communication
when necessary is a great transmission.
It is a transmission systems of electromagnetic signals.
Characterics Electromagnetic waves
Intensity and frecuency controlled
The operation is based on the conversation
of sound waves in electromagnetic waves.
These are transmitted by cable or waves
radiated. It is an alternation between the
emitter and receptor that allows a real-time
• There are a lot of types of
dynamic, ribbon). But all
of these are based in the
same process: waves
vibrate a membrane is
used to modify and
modulate an electric
• They do the opposite that
transform electric current
into sound waves. For do
this they used the
THE HISTORY OF THE TELEPHONE
1854: Antonio Meucci invent an electromagnetic
for the transmision of voice.
1876: Alexander Graham Bell he develops an
1887: First telephone lines in Germany.
1889: Automated telephone system.
1891: First telephone cable service in the USA
and in France.
1947: First movil phone. The sistem expanded since
1952:First Telecomunication satellite, it can recibed
and transmited waves of radio and television.
Nowadays: All the telephones are avanced a lot,
and we have very modern movil phones.
It turns the sound in electrical impulses
The sounds are caught by the microphones
The sound comes to the antenna
There takes place an electrical variation, which
finally comes to your house
The recipients of your radio transform the sign into
System of emission (station of radio)
System of transmission (high or clear places)
System of receipt (every radio set)
Modulation in frequiency (FM):
- Carrying wave
- Reduces not wished noise
distorsions on the sound
- Quality of de trasmission is improved
- Minor scope
Modulation in extent (AM):
- Carrying wave
- Typical of issures of short, average and long wave
- Great scope
- Telecommunication medium
- Transmitting and receiving moving color
images and sound
- Uses a broadcasting mechanism
- Recipient : television
- Transmission can be made by
To realize a television
broadcast we need: camera
to recive the images and a
system to record the sound.
In 1911 the physicist russian Zworykin realizes the first experimental
transmission of a static image.
On 25 December 1926, Kenjiro Takayanagi demonstrated a TV
system with a 40-line resolution.
Eperiments of Guillermo González Camarena began in 1931 and led
to a patent for the color television in 1940.
In 1950 takes place the invention of the system of three cannons for the
television in color.
In 1972 are formed the first commercial nets of television by cable, in
In 1979 is invented the first recipient of television with a flat screen of liquid
The World Day of the Television is celebrated on November
21 in commemoration of the date in which the first World Forum
of Television was celebrated in 1996 in the United Nations.