In signal processing and identification, the concept of energy and power of a signal are often used.
The energy over t = ∞ and t = − ∞ expanded in resistance (R) after applying a voltage e(t) can be expressed as
This energy is called as normalized energy for R = 1Ω.
Therefore, the energy in a signal f(t) by analogy we can write
The signal is said to be energy signal if the energy is finite.
For energy signal, and it always satisfies the absolute integrability criterion ...