Consider a model to understand the properties of a signal. Generally, the signals occurring in nature are very complex. Although they do have the same properties its not very easy to understand them if a person is new to the topic. So, we have chosen to study a sumple signal model as an example. A sine or Cosine wave is a simple signal. It is very ideal for a student to choose one of these signals as they are easy to generate and it is possible to set up an experiment in the lab to study them. Some of the common experiments that use Sinusoidal Signal are the AC power signal, voltage signal, oscillating pendulum, etc. A sinusoidal signal can be generated very easily, by passing a a square wave to a low pass filter or by using a crystal. Besides the advantage of being able to generate the signal using simple lab equipment it is also cheap to produce the Sine signal.

In the figure the Value A denotes the amplitude or the signal strength of the Sine wave. The wavelength is the path covered by the signal during the time 'period' shown by the bi-directional arrow along the time-axis.