We discuss application of F-transform with respect to raised cosine generalized uniform fuzzy partition to analysis of time series under assumption that the time series can be additively decomposed into trend-cycle, seasonal component and noise. We focus that when setting reasonably width of the basic functions, inverse F-transform of the time series is good approximation of its trend-cycle. This mean that we can determine a generalized fuzzy partition such that F-transform completely remove seasonal component and noise.