In signal processing, the energy E s {\displaystyle E_{s}} of a continuous-time signal x is defined as the area under the squared magnitude of the considered signal i.e., mathematically E s = ⟨ x, x ⟩ = ∫ − ∞ ∞ | x | 2 d t {\displaystyle E_{s}\ \ =\ \ \langle x,x\rangle \ \ =\int _{-\infty }^{\infty }{|x|^{2}}dt} Unit of E s {\displaystyle E_{s}} will be 2. Wikipedia