In this era of signal processing, the understanding of energy and power signals holds an utmost importance.
Signals, as carriers of information, exhibit diverse characteristics that necessitate a nuanced comprehension of their behavior. Energy signals and power signals represent two essential classifications, each delineating distinct attributes that shape their roles in various applications.
In this article, we are going to see the difference between Energy and Power Signals.
What is Energy Signal ?
An energy signal is a signal whose total energy is finite.
When 0 < E < \infty . For an energy signal, the average power is zero, P=0.
The non-periodic signals are the examples of energy signals.
What is Power Signal?
A power signal is a signal whose power is finite or non-zero.i.e. 0< P < \infty . For a power signal, the total energy E= \infty . The periodic signals ar the examples of power signals.
Difference between Energy and Power Signal
First of all let us understand the difference between energy and power.
i) Energy represents the capacity to do some work. Whereas the Power represent the rate at which the work is done/Energy spend to do the particular work.
ii) Energy can be positive or negative. Power is always positive.
The reason that why Energy is positive or negative is as follows, we know that Energy is the sum of Kinetic energy and potential energy.
Energy = K.E + P.E
K.E is always positive as it depends on mass , mass cannot be negative. Whereas Potential Energy can be positive or negative. So, therefore, we can say that Energy can be positive or negative.
Whereas Power signal is always positive because this Power is nothing but the Average Power. Average Power is calculated from the average instantaneous power.
This instantaneous power is given by the square of the signal. And there is a square so, power is always positive.
Any signal whether positive or negative, due to the presence of square it will always be positive.
iii) The Energy signal is the non-periodic signal and Power signal is the Periodic signal.
A periodic signal is a signal which repeats after a particular interval of time. So, Power signal is a periodic signal as it repeats after a particular period of time. Energy signal is non-periodic because it does not follow the particular pattern.
We can see the diagrammatic representation of power signal and energy signal below.
iv) Energy signal has NO power and Power signal has infinite energy.
Let us summarize the difference in the form of table.
| Sr. No. | Energy Signal | Power Signal |
| 1. | It is the signal whose total energy is finite. | It is the signal whose power is finite or non-zero. |
| 2. | It is given by E=\int_{-T}^T\vert x(t)\vert^2dt. | It is given by the formula P=\frac12\int_0^T\vert x(t)\vert^2dt |
| 3. | Energy can be positive or negative. | Power is always positive |
| 4. | Energy signal is the non-periodic signal | Power signal is the Periodic signal. |
| 5. | Energy Signal has No Power. | Power signal has infinite energy. |
Hope, so !! The difference between Energy and power signal is cleared to you.
