Deterministic and Random Signals

Hi friends, in this article we will learn some basic concepts about Deterministic and Random Signals. We will cover definitions and examples of Deterministic and Random Signal.

Deterministic signal

Deterministic signals can be described by a mathematical expression, lookup table or some well-defined rule.

Examples: Sine wave, cosine wave, square wave, etc.

[caption id="attachment_1559" align="aligncenter" width="287"]Deterministic signal Deterministic signal[/caption]

A sine wave can be represented mathematically as,

x(t) = A sin (2πft)


  • A is the amplitude of a signal

  • f = frequency of a signal

Note: The deterministic signals such as sine wave, cosine wave, etc. are periodic in nature. Besides this, some deterministic signals may not be periodic. The exponential signal is an example of a non-periodic signal.

Random Signal

A signal which cannot be described by any mathematical expression is called as a random signal. Therefore, it is not possible to predict the amplitude of such signals at a given instant of time.

Example: A good example of a random signal is noise in the communication signal. Below figure shows one of the random signals.

[caption id="attachment_1558" align="aligncenter" width="283"]Random Signal Random Signal[/caption]

Recommended articles to read:

  1. Introductions to Signals and Systems

  2. Category: Signals and Systems