Left panel: diagram describing the morphology of the PSD profiles according to Eq. (4) for all possible values of the parameters α and K. Different curves represent the boundaries of subsets of the parameters for which the PSD exhibits a double-feature. The red curve encloses set C_M of the doubly peaked power spectra. The other curves correspond to the sets of power spectra with a nontrivial structure of inflection points C_I0 (blue), C_I1 (magenta) and C_Iq (green). Right panel: three examples of the PSD profiles. A double-peaked power spectrum (red) with parameters α = 0.94 and K = 0.01 (i.e., the values within set C_M, as denoted by the red point in the left panel), doubly-broken power spectrum with a single local maximum (magenta) corresponding to α = 0.85 and K = 0.08 (the magenta point within set C_I1 and outside of C_M) and a power spectrum with single maximum and break (green) with α = 0.5 and K = 0.5 (the green point outside of C_Iq).