New
technologies
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.
Advantages
Disadvantages
cheaper
reliability
Very fast
The
installation
is difficult
Physical
access
Difficulty and
expansion
expectations
Conventional cable:
It is a copper wire, protected by an insulating
cover.
Transmitting the converted electromagnetic
signal
into electrical current, or a series of specific
impulses.
Often used in wireline systems
Coaxial cable:
-This cable is a moderately immne to outside
electromagnetic interference compared to
conventional cable.
-It is also well suited for broadband applications.
-Expensible and inflesible
Optic fibre cable:
-Has much grta transmission than the other tipes
of cables.
-It is inmmune to outside interferences.
-It is used in the higher rate communications
places.
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.
Advantage
Possibility of sending of a same fiber up to 100
light beams and high speeds are achieved
Disvantage
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
fiber.
Is applied in the field of communication
when necessary is a great transmission.
Analogical
telecommunications
It is a transmission systems of electromagnetic signals.
Very fast
Characterics Electromagnetic waves
Intensity and frecuency controlled
Telephone
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
conversation
Fundamental objects
Microphones
• There are a lot of types of
microphones (coal,
dynamic, ribbon). But all
of these are based in the
same process: waves
vibrate a membrane is
used to modify and
modulate an electric
current.
Headphones
• They do the opposite that
microphone, they
transform electric current
into sound waves. For do
this they used the
electromagnet.
THE HISTORY OF THE TELEPHONE
1854: Antonio Meucci invent an electromagnetic
for the transmision of voice.
1876: Alexander Graham Bell he develops an
operating telephone.
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
1893.
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.
THE RADIO
FUNCTIONING
 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
sound
COMPONENTS
 System of emission (station of radio)
 System of transmission (high or clear places)
 System of receipt (every radio set)
 Modulation in frequiency (FM):
variable frequiency
- Carrying wave
constant extent
- Reduces not wished noise
interferences
distorsions on the sound
- Quality of de trasmission is improved
- Minor scope
FREQUENCY
 Modulation in extent (AM):
constant frequency
- Carrying wave
variable extent
- Typical of issures of short, average and long wave
- Great scope
HISTORY
TELEVISION
- Telecommunication medium
- Transmitting and receiving moving color
images and sound
- Uses a broadcasting mechanism
- Recipient : television
- Transmission can be made by
-Radio waves
-Networks
cable television
- Satellite
television
To realize a television
broadcast we need: camera
to recive the images and a
system to record the sound.
TREATMENT OF THE IMAGE
Images in color 3 faeces of electrons
Red
Green
Blue
London
 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
EEUU.
 In 1979 is invented the first recipient of television with a flat screen of liquid
crystal.
 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.
THE END
Cristina Céspedes
Laura Fernández
Paloma González
Lourdes Sevilla
Julia Soubrier