## Periodic Signal

A signal is considered to be periodic signal if it completes a pattern within a measurable time frame, called a period and repeats that pattern over identical subsequent periods.

A period is defined as the amount of time (expressed in seconds) required to complete one full cycle. Sinusoidal wave, cosine wave, triangle wave and square wave are example of periodic signal.

Periodic signals are more commonly identified by their
frequency (*f*) rather than their
period. The frequency of a signal is the inverse of the period. Mathematically,
this means that:

*F*=*1/T*

The frequency of a signal tells us how many times the signal
repeats itself during one second. Units of frequency are in cycles per second
or Hertz (*Hz*). Therefore, a signal
with a frequency of 100Hz goes through 100 cycles (Periods) in one second (the
period of the signal is 0.01 seconds.

### What You Need To Know About Periodic Signal

- A signal is considered periodic if it repeats itself after a specific interval of time.
- Periodic signal is a signal which repeats itself after specific interval of time.
- Periodic signal can be represented by a mathematical equation.
- The value of periodic signal can be determined at any point in time.
- Periodic signal are deterministic signals.
- All bounded periodic signals are power signals because they do not converge to a finite value so their energy is infinite and their power is finite. The signal is an energy signal if its energy is finite and power is zero.
- Sinusoidal wave, cosine wave, triangle wave and square wave are example of periodic signal

## Aperiodic Signal

Aperiodic signal is a signal which does not repeat itself after a specific interval of time. In order to show that an aperiodic signal can be expressed as a continuous sum (or integral) of infinite exponentials, a limiting process is applied.

Example of aperiodic signal is signal created by microphone or telephone when one or two words are pronounced. Also, signal propagated by AM radio station or FM radio stations are all aperiodic signal.

### What You Need To Know About Aperiodic (Non-periodic) Signal

- A signal is considered aperiodic signal when it does not repeat its pattern over a period or interval of time.
- Aperiodic signal is a signal which does not repeat itself after a specific interval of time.
- Aperiodic signal cannot be represented by any mathematical equation.
- The value of aperiodic signal cannot be determined with certainty at any given point of time.
- Aperiodic signal are random signals.
- An aperiodic function never repeats, although technically an aperiodic function can be considered like a periodic function with an infinite period.
- Example of aperiodic signal is signal created by microphone or telephone when one or two words are pronounced. Also, signal propagated by AM radio station or FM radio stations are all aperiodic signal.

## Differences Between Periodic And Aperiodic Signal In Tabular Form

BASIS OF COMPARISON |
PERIODIC SIGNAL |
APERIODIC SIGNAL |

Description | A signal is considered periodic if it repeats itself after a specific interval of time. | A signal is considered aperiodic signal when it does not repeat its pattern over a period or interval of time. |

Definition | Periodic signal is a signal which repeats itself after specific interval of time. | Aperiodic signal is a signal which does not repeat itself after a specific interval of time. |

Representation | Periodic signal can be represented by a mathematical equation. | Aperiodic signal cannot be represented by any mathematical equation. |

Determination Of Value
| The value of periodic signal can be determined at any point in time. | The value of aperiodic signal cannot be determined with certainty at any given point of time. |

Type of Signal | Periodic signal are deterministic signals. | Aperiodic signal are random signals. |

Infinite Period | All bounded periodic signals are power signals because they do not converge to a finite value so their energy is infinite and their power is finite. The signal is an energy signal if its energy is finite and power is zero. | An aperiodic function never repeats, although technically an aperiodic function can be considered like a periodic function with an infinite period. |

Examples | Sinusoidal wave, cosine wave, triangle wave and square wave are example of periodic signal | Example of aperiodic signal is signal created by microphone or telephone when one or two words are pronounced. Also, signal propagated by AM radio station or FM radio stations are all aperiodic signal. |