What are Deterministic and Random Signals? with Examples and Differences

Signals are all around us, carrying information in various forms. A signal is a function that carries information about a physical phenomenon.

It varies with an independent variable, such as space, time, or density.

In essence, anything that conveys information can be considered a signal. Examples include: temperature of a room, voltage, and current in an electronic circuit, digital images, video, or audio etc.

We can broadly categorize signals into two types: deterministic and random signals.

What are Deterministic Signals?

Deterministic signals are those that can be completely predicted and described by a mathematical equation or rule. They have a fixed pattern and behave consistently over time.


Another definition is, a deterministic signal is a signal that has no uncertainty with respect to its value at any instant of time.

This is quite similar to Sine, since at any instant of time (t) there is a corresponding or defined value for the signal.

deterministic signal

What are Random Signals?

Random signals also known as non-deterministic signals, on the other hand, are unpredictable and exhibit randomness in their values.

They cannot be precisely described by a single equation but are characterized by their statistical properties like mean, variance, and probability distribution.

random signal


Another definition is, a random signal is a signal that has uncertainty with respect to its value at any instant of time. It is defined in probabilistic terms, as there is no define value.

Differences between Deterministic and Random Signals

Deterministic SignalsRandom Signals
PredictabilityCompletely predictableUnpredictable
DescriptionDefined by a mathematical equation or ruleCharacterized by statistical properties
PatternFixed and consistentRandom and irregular
ExamplesSine wave, square wave, music signal (when played repeatedly)Noise, thermal fluctuations, ECG signal

Examples of deterministic signals:

Examples of random signals:

Wrap Up

As a wrap up, understanding the nature of deterministic and random signals is essential for various applications.

For example, in communication systems, we aim to transmit deterministic signals (like information data) while minimizing the impact of random noise.

In medical diagnosis, analyzing random signals like the ECG can reveal valuable insights about a patient’s health.


1. Why is the predictability of signals crucial in communication systems?

The predictability of signals in communication systems ensures the accurate transmission of information while reducing the impact of random noise.

2. How do deterministic signals differ from random signals in terms of patterns?

Deterministic signals exhibit fixed and consistent patterns, while random signals dance to an irregular beat, lacking fixed patterns.

3. Can you provide real-world examples where the understanding of random signals is vital?

Understanding random signals is important in medical diagnosis, especially in analyzing signals like the ECG to gain insights into a patient’s health.