DATA COMMUNICATION PRINCIPLES Channel Impairments Channel Impairments A

DATA COMMUNICATION PRINCIPLES : Channel Impairments

Channel Impairments A transmission channel is the path of information signal. It could be made of matter, such as metals, water and air, or it could be the space. A channel is characterized by the speed at which information could pass through it without significant deterioration. Sometimes, a channel is defined as a certain amount of bandwidth of the medium. In fact, the term ‘transmission medium’ is more popularly used to convey the matter type (metal, glass or air) rather than the channel. However, for this section, we use the terms transmission medium and channel interchangeably. Channel affects the signal in many ways. Some of the effect is related to the radiation of energy that results in weakening of the signal as it moves away from its origin (attenuation). Other effect is because of the frequency selective behavior of the channel that results in different frequency components of the same signal arriving at the destination with different strengths. Yet, some of the channel impairments are related to the electronic noise created due to the random motion of electrons, atoms, and molecules. Here is a brief account of each.

REFERENCES • Ahmad A. - Data Communication Principles. For Fixed and Wireless Networks • Cornelius T. Leondes - Database and Data Communication Network Systems, Three-Volume Set_. . -Academic Press