sdr.energy(x: ArrayLike) → float Measures the energy of a time-domain signal \(x[n]\). \[E = \sum_{n=0}^{N-1} \left| x[n] \right|^2\] Parameters:¶ x: ArrayLike¶The time-domain signal \(x[n]\) to measure. Returns:¶ The energy of \(x[n]\) in units^2.