| In nowadays communication becomes our daily | | | | There are three types of basic elements to |
| lives in different ways that it is very easy to | | | | every communications system that is the |
| overlook the multitude of its facets. Cell phones | | | | transmitter, channel and receiver. Transmitter is |
| at our hands, television and radios in our sitting | | | | located at one point in space, the receiver is |
| rooms, computer terminals with access to the | | | | located at some other point separate from the |
| Internet in our offices and homes, and the | | | | transmitter, and the channel is the physical |
| newspapers are capable of delivering a rapid | | | | medium that connects them. The purpose of the |
| communications around the world. Communication | | | | transmitter is to convert the message signal |
| provides the senses for ships on the high seas, | | | | produced by the source of information into a |
| aircraft in the flight and the rockets and satellites | | | | form suitable for transmission over the channel, |
| in space. Communication through a wireless phone | | | | as the transmitted signal propagates along the |
| keeps a car driver in touch with the office or | | | | channel; it is distorted due to channel |
| home miles away. Communication keeps a | | | | imperfections. Noise and interfacing signals are |
| weather forecaster informed of conditions | | | | added to the channel output, with the result that |
| measured by a multitude of sensors. | | | | the received signal is a corrupted version of the |
| Communication involves implicitly the transmission | | | | transmitted signal. The receiver has the task of |
| of information from point to point through a | | | | operating on the received signal so as to |
| succession of process. | | | | reconstruct a recognizable form of the original |
| Generation of a message signal computer data, | | | | message signal for a user. |
| pictures, sense, voice, music. | | | | Broadcasting which involves the use of a single |
| Description of that message signal with a certain | | | | powerful transmitter and numerous receivers that |
| measure of precision by a set of symbols. | | | | are relatively inexpensive to build. Here information |
| Encoding symbols in a form that is suitable for | | | | bearing signals flow only in one direction. |
| transmission over a physical medium of interest. | | | | Point to point communication in which the |
| Transmission of the encoded symbols to the | | | | communication process takes place over a link |
| desired destination. | | | | between a single transmitter and a receiver. In |
| Decoding and reproduction of the original symbols. | | | | this case there is usually a bidirectional flow of |
| The re-creation of the original message signal with | | | | information bearing signals, which requires the use |
| a definable degradation in quality, the degradation | | | | of a transmitter and receiver at each end of the |
| is caused by imperfections in the system. | | | | link. |
| There are many types of communications that | | | | Broadcasting mode of communication is |
| do not directly involve the human mind in real life. | | | | exemplified by radio and television and the |
| There are computer communications involving | | | | ubiquitous telephone provides the means for one |
| communication between two or more computers, | | | | form of point to point communication. There is |
| human decisions may follow in setting up the | | | | another point to point communication is the link |
| programs or commands for the computer, or in | | | | between an Earth station and a robot navigating |
| monitoring the results. | | | | the surface of a distant planet. |