Hi Jannik, The bmin and bmax parameters are the bandwidth min and max of the gaussian filters used in the FTAN algorithm. The FTAN applies a set a gaussian filters to the seismograms with different central frequencies. The width of the filter (in Hz) for the minimum central frequency is bmin and vice versa for bmax. The width for the intermediate filters increases linearly between bmin and bmax. These parameters are equivalent to the "alpha" parameters in this paper defining the FTAN: Herrmann, R. B. (1973). Some aspects of band-pass filtering of surface waves. *Bulletin of the Seismological Society of America*, *63*(2), 663-671. Hope it helps! Aurelien Le jeu. 26 nov. 2020 à 17:30, Jannik Kühn <jfkuehn(a)gfz-potsdam.de> a écrit : -- ========================== Postdoctoral associate Department of Earth, Atmospheric and Planetary Sciences Massachusetts Institute of Technology 54-526 Cambridge, MA 02139-4307 phone: 617-253-5051 e-mail: mordret(a)mit.edu web: http://web.mit.edu/mordret/www