Signals
Information is exchanged over the network in the form of signals. Data is transmitted over the network as signals. These signals may be analog or digital depending on the type of data sent. Analog data is sent in the form of analog signals and digital data is sent in the form of digital signals.A signal travels in the form of a wave. This wave is received by receiver machine from where information is gained in the same form as it was sent, if no error occur.
Analog signals
Above is an analog signal, as it is represented on a piece of paper. An analog signal consists of infinite values of amplitude, and it is visible from the above diagram. If these values seem to repeat over an interval of time, such a signal is known as a periodic analog signal. e.g. a sine wave. And when these values do not repeat themselves, such a signal is known as a non-periodic analog signal.
Digital signals
A digital signal has definite number of amplitude values. Digital signals can also be periodic and non-periodic. Non-periodic digital signals are encountered in practical life.
