Data travels from one point to other point by using electromagnetic signals in a communications system. Two types of electromagnetic signals exist. One is called analog signal and other is called digital signal.In analog signal intensity varies smoothly with the passage of time. Examples of analog signal are voice and video, because in both cases frequency varies smoothly with the passage of time. Most familiar form of analog data is audio which the form of acoustic sound waves. Analog signal can propagate over a variety of media; examples are wire media (Twisted pair, Coaxial cable etc) and unguided media (atmosphere or space propagation).
In digital signal intensity does not vary in a smooth fashion as it maintains a constant level for some period of time and then changes to another level. Text and integers are the examples of digital signals. A digital signal may be transmitted over a wire medium. It represents a stream of 1s and 0s which may represent digital data or may be an encoding of analog data. Advantage of digital signal is that, it is cheaper than analog signal. Disadvantage of digital signal is that, it suffers more from attenuation than analog signal.
In digital signal intensity does not vary in a smooth fashion as it maintains a constant level for some period of time and then changes to another level. Text and integers are the examples of digital signals. A digital signal may be transmitted over a wire medium. It represents a stream of 1s and 0s which may represent digital data or may be an encoding of analog data. Advantage of digital signal is that, it is cheaper than analog signal. Disadvantage of digital signal is that, it suffers more from attenuation than analog signal.