**2. Considered Methods**

In this section, the algorithms considered for the comparison will be briefly described. At first, some non-parametric algorithms will be presented (IFFT-2p, IFFT-3p, IFFTc), they are all based on the use of a fast Fourier transform (FFT) algorithm, but they improve the spectral resolution of the discrete Fourier transform (DFT) algorithm, with interpolation techniques. Then three parametric algorithms will be introduced (MUSIC, ESPRIT, and IWPA), based on approaches different from the DFT evaluation. Since almost any signal can be represented as a multi-tone signal (1), composed of the sum of *Ns* sinusoids with amplitude, *Ai*, and phase, *φi*; all the algorithms will be compared with respect to this signal family.

$$\mathbf{x}(t) = \sum\_{i=1}^{N\_b} A\_i \sin(2\pi f\_i t + \phi\_i). \tag{1}$$
