Chapter 1 : Telecommunication Introduction and Model
Topics covered in this snack-sized chapter:
Telecommunications engineering, or telecom engineering, is an engineering discipline that brings together electrical engineering with computer science to enhance telecommunication systems.
The word telecommunication was originated from the French word télécommunication
in 1932.
Telecommunication is a compound of the Greek prefix ‘tele’ meaning far off, and the Latin word 'communicare’ meaning to make common, to share, or to impart.
Telecommunication is the transmission of signals over a distance for the purpose of communication.
Telecommunication is the science and technology of sending and receiving information by electromagnetic means.
Early telecommunications included smoke signals and drums.
In 1792, a French engineer, built the first visual telegraphy (or semaphore) system.
In 1831 – Professor Joseph Henry, Albany, NY – Ring a bell at a distance by connecting and disconnecting wires.
The first commercial electrical telegraph use began on April 9, 1839.
The electric telephone was invented in the 1870s, based on earlier work with harmonic (multi-signal) telegraphs.
In 1895: Invention of the radio by Marconi.
In December 1901, Guglielmo Marconi established wireless communication between St. John's, Newfoundland and Poldhu, Cornwall (England).
In October 1925, Baird was successful in obtaining moving pictures with halftone shades, which were by most accounts the first true television pictures.
In 1965 Thomas Marill and Lawrence G. Roberts created the first wide area network (WAN). This was an immediate precursor to the ARPANET, Roberts was its program manager.
Commercial services using X.25 (a standard protocol suit for packet switched WAN) were deployed in 1972, and later used as an underlying infrastructure for expanding TCP/IP networks.
Inmarsat: The oldest satellite phone operator, founded in 1979.
Audio signals:
- An audio signal is a representation of sound, typically as an electrical voltage.
- Audio signals have frequencies in the audio frequency range of roughly 20 to 20,000 Hz (the limits of human hearing).
- Audio signals may be synthesized directly, or may originate at a transducer such as a microphone, musical instrument pickup, phonograph cartridge, or tape head.
- Loudspeakers or headphones convert an electrical audio signal into sound.
| Prehistoric
| Communication drums, Horns
|
| 1838
| Electrical telegraph
|
| 1876
| Telephone
|
| 1880
| Photo phone
|
| 1895
| Radio
|
