Fourier spectra in 1D and 2D for X Sgr calculated based on Coralie14 CCFs using FAMIAS software. Left panels: frequency spectra of original data. Right panel: frequency spectra after pre-whitening with fundamental mode and its harmonic. Pre-whitened frequencies are marked in the bottom panel with red lines. Bottom panels: 2D spectra, where amplitude is color-coded. Frequencies found in other methods are marked with white arrows and labeled. Top panels: 1D mean Fourier spectra.