Comparison between the analytical precession model (blue) and numerical integration (red), close to stable equilibrium. On the leftmost column: the components of the spin of the primary, in the time domain. The corresponding Discrete Fourier Transform ℱ{ŝ₁} is given in absolute value (power spectrum in decibels, middle column), and in complex argument (rightmost column). The time and frequency axes are expressed in the re-scaled dimensionless units.