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| Voices Across the Earth
Voices Across the Earth
Originaldokument enthält an dieser Stelle eine Grafik!
Original document contains a graphic at this position!
Voices
Originaldokument enthält an dieser Stelle eine Grafik!
Original document contains a graphic at this position!
Across the Earth
Thomas Lieber
Mag. Schaludek-Paletscheck
Originaldokument enthält an dieser Stelle eine Grafik!
Original document contains a graphic at this position!
Table of
Contents:
Voices Across the
Earth
1.
Introduction............................................................................................3
2. Main Part
...............................................................................................3
2.1 The First Electronic
Communication..............................................3
2.2 Transmitting
Voices.....................................................................4
2.3 Radio
Waves.................................................................................5
2.4 Recording
Sound..........................................................................6
2.5 In the Modern
World....................................................................6
3.
Appendix.................................................................................................7
4.
Handout..................................................................................................8
5.
Notes.......................................................................................................9
6.Glossary.................................................................................................10
Voices Across the
Earth
1. Introduction:
First I want to say that communication links between people have always
been important.
Today we live in the Communications Age and we owe this to inventors in
the last century. Now I want to tell you something about these
inventors.
In ancient times, bonfires on hilltops were used to signalling danger.
The North American Indians used smoke signals and the Romans flashed messages
with mirrors turned to catch the sun. Sending messages in this way worked well
in certain circumstances. If the messages were complicated, a code had to be
used, which had to be understood by everyone. The only other way of
communicating was to send a written message, which took time if the people
involved lived any distance apart.
2. Main Part:
2.1 The First Electronic Communication:
The invention of electric power revealed many possibilities for
communication. The first telegraph was patented by a British scientist, Sir
Charles Wheatstone and an Indian Army Officer, Sir William Cooke, in 1837. It
used needles which pointed at different letters in response to electric
currents. Some codes were created to communicate with this new invention. In the
following picture we can see the different codes.
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A
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B
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C
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D
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E
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Semaphore code
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•
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• •
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•
•
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•
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Morse code
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•
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• •
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Five-unit code
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The Semaphore code, developed in 1794, used a system of moving arms
worked by ropes to create symbols for each letter. Samuel Morse’s code
could be transmitted along a wire using a key. This code is shown as dots and
dashes. The code could also be transmitted with flashing lights. The Five-unit
code was developed from the Morse code for using with a teleprinter, an
instrument for typing telegraphs to be sent along telephone wires.
Morse established the first telegraph line between Washington and
Baltimore in 1844. By the 1860’s telegraph wires connected the East and
West Coast of the United States and there was a cable across the Atlantic to
Europe.
2.2 Transmitting Voices
Communication by telegraph was quicker than sending a letter, but slower
than speaking to the person directly. If coded messages could be sent along
electric wires, could the human voice also be transmitted?
Alexander Graham Bell gave us the answer. He knew that sounds make
vibrations on the eardrum which the brain translates to make sense of them. His
idea was to make a transmitter with a disc which would vibrate when struck by
sound waves, in the same way as the eardrum. Sound vibrations from the
transmitter would pass along a wire to a receiver which would also have a
vibration disc. This receiver would convert the sound vibrations back into
words. On March 6, 1876, the first words were transmitted. The telephone had
been invented.
Now, in theory, it was possible to communicate by telephone with
anywhere in the world. But one problem was still how to link up telephone lines
so that people could ring up anyone they liked.
The answer was a telephone exchange, where lines from different
telephone subscribers could be plugged into a switchboard to connect them to
each other.
By 1885, there were 140.000 subscribers and 800 telephone exchanges. The
first telephone exchanges were manual, which meant that operators sat in the
exchange and plugged the lines into a switchboard by hand to connect calls.
Today the calls are connected by computers.
2.3 Radio Waves
In the middle of the nineteenth century, scientists began to examine the
idea of transmitting sounds without wires. The first man to introduce the idea
of electromagnetic waves was the British scientist, James Clerk Maxwell, who
demonstrated that light is an electromagnetic wave and suggested the idea of
radio waves. In 1888, the German scientist, Heinrich Hertz, produced and
detected radio waves with a simple transmitter.
When Guglielmo Marconi, an Italien electronic engineer, read a newspaper
report about electromagnetic waves in 1894, he resolved to find out if these
“wireless“ waves could be used to transmit sound. To make the
receiver more sensitive to the signals, he connected a long vertical wire with
the receiver. Marconi worked on this invention until he managed to send a signal
from his house to a field two kilometres away.
Electromagnetic waves such as light and radio waves travel faster than
sound. To transmit sound by radio waves, a microphone in a transmitter converts
them into electrical signals. The signals pass to an aerial in the transmitter
and spread out as radio waves. The aerial on the receiver picks up the waves and
a loudspeaker turns them back into sound.
In 1899, Marconi transmitted a message about fifty kilometres across the
English Channel and in 1901 he made the first radio link across the Atlantic. In
1920, the Marconi Company broadcast the first British radio
programme.
2.4 Recording Sound
Another new idea was the concept of storing sounds on a solid material
so that they could be played over and over again. One of the greatest inventors,
Thomas Alva Edison, invented the phonograph for recording and playing sound. He
got the idea from the telephone, which had recently been invented. He
constructed a recording machine and shouted the world “HELLO“ into
it. The sound that came back to him was an indistinct but definite
“HELLO“.
Edison’s first recording was the nursery rhyme “Mary had a
little lamb“. Edison’s invention brought him worldwide fame, but his
phonograph was very basic. The sound quality was not good and the cylinders did
not last long. Edison was more interested in thinking up new ideas than in
perfecting his inventions and it was left to others to improve on the
phonograph.
After Emile Berliner had found a way to make records in 1887, he went on
to design a machine for playing them: the “gramophone“. The early
gramophone had a large horn for making the record sound louder. The machine had
to be wound up with a handle to make the turntable revolve.
2.5 In the Modern World
Today, all these methods of communication have moved forward in ways
which their inventors could never have imagined. People can now listen to the
music of a complete orchestra, with the sound of each instrument faithfully
reproduced.
Equipment which produces high quality and accurate sound reproducing is
known as high-fidelity or “hi-fi“ equipment.
The latest method of reproducing music is digital recording, which is
stored as a digital code and is translated into sound by a computerized player.
The compact disc is the best-known form of digital sound recording. It
produces the finest-quality sound available at the moment.
The telephone can link people on opposite sides of the world in seconds,
people have telephones in their cars and a telephone which shows a picture of
the caller and recipent on a small screen is now becoming available. Documents
are fed into a fax machine which turns the text and pictures into electronic
signals. The signals are sent along the telephone wires and a fax reciever at
the other end turns them back into exact copies of the documents
sent.
Communications satellites have made it possible to link up distant
corners of the world and even to communicate with craft in space.
One day in the future we may be able to use Marconi’s idea to
communicate with extraterrestrial
civilizations.
3. Appendix:
The communication codes:
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A
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B
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C
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D
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E
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Semaphore code
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•
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•
• •
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•
•
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•
•
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•
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Morse code
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•
•
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• •
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• •
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Five-unit code
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4. Handout:
Contents:
In ancient times:
Bonfires on hilltops were used to signalling danger - North American
Indians used
smoke signals - Romans flashed messages with mirrors
In the electronic age:
first telegraph - British scientist, Sir Charles Wheatstone - Codes
were created to
communicate with this invention
first telephone - Alexander Graham Bell - on March 6, 1876, the first
words were
transmitted
first radio - Guglielmo Marconi - 1899, Marconi transmitted a message
about
fifty kilometres - In 1920, the Marconi Company broadcast the first
British radio
programme.
Recording Sound:
first recording - Thomas Alva Edison - 1877, Edison invented the
phonograph
In the modern world:
communication today: TV, Handy, Inet, Cserve, ...
recording today: CD, MD, DCC, MC, (LP), ...
5.
Notes:
6. Glossary:
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English
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German
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ancient
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alt, altertümlich
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bonfire
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Feuer im Freien
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circumstance
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Umstand
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reveal
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freigeben, (Geheimnis) aufdecken
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possibility
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Möglichkeit
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in response
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Antwort
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established
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bestehend, feststehend
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quick
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schnell
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to receive
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empfangen
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eardrum
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Trommelfeld
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exchange
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ausstauschen
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subscribers
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Teilnehmer
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plug
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elektr. Stecker, Stöpsel
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switchboard
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Schalttafel, Telefonzentrale
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spread out
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ausbreiten
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broadcast
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verbreiten (Nachricht)
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indistinct
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undeutlich
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definite
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endgültig
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wound up
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hochkurbeln
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revolve
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sich drehen
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high-fidelity
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hohe (elektr.) Klangtreue
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recipient
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Empfänger
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extraterrestrial civilizations
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außerirdische Zivilisation
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