The elements of a telecommunication system are a transmitter, a medium (line) and possibly a channel imposed upon the medium (see baseband and broadband as well as multiplexing), and a receiver.
The transmitter is a device that transforms or encodes the message into a physical phenomenon; the signal. The transmission medium, by its physical nature, is likely to modify or degrade the signal on its path from the transmitter to the receiver. The receiver may therefore require a decoding mechanism to recover the message from the received signal. This mechanism can be designed to tolerate a significant degree of signal degradation. Sometimes, the final "receiver" is the human eye, ear (or other sensory organ) and the recovery of the message is done by the brain (see psychoacoustics.)
Telecommunication can be point-to-point, point-to-multipoint or broadcasting, which is a particular form of point-to-multipoint that goes only from the transmitter to the receivers.
One of the roles of the telecommunications engineer is to analyse the physical properties of the line or transmission medium, and the statistical properties of the message in order to design the most effective encoding and decoding mechanisms.
When systems are designed to communicate through human sensory organs (mainly those for vision and hearing), physiological and psychological characteristics of human perception must be taken into account. Certain types of defect, while objectively measurable, are not readily apparent to human perception while others are disproportionately apparent. The cost of a system can therefore be reduced by choosing to omit certain information. There is clearly a tradeoff between reduced cost and user demand for higher quality, and this is an important economic consideration for those who plan systems.
The field of telecommunication is no doubt one of the most exciting occupational fields that modern society has to offer. New technology is constantly being developed and finds its applications in the technical systems that make up a telecommunications network. This creates opportunities for developing existing services further, and introducing completely new ones. |
