The damages caused to a travelling signal are called impairments. Following three are the main varieties of impairments in a signal:
The damage caused in the power of a signal is called attenuation. Usually it is caused due to obstacles in the media like- resistance in wires or storms and tornados in waves. The amplitude of waves in this impairment gets decreased gradually.
In this impairment, the shape of wave gets damaged. The harmony contained in the signal gets affected and serious changes to the phase of wave occur.
Noise is nothing but an unwanted signal that gets attached with our original signal. Usually the neighboring frequencies make this kind of damages. In modern communications, use of PASS Bands has almost avoided this kind of damages.