fScan Reference Manual, Chapter 2 (CmdLineOptions:Expr): tsmooth
usage: -expr tsmooth twin [flag]
TSMOOTH uses sliding window averaging across time to smooth each voxel time series.
TWIN indicates how many contiguous time points to average together in the sliding window.
By default TWIN is the number of time points, but if FLAG&1 (odd value) then TWIN is in seconds.
FLAG (combine options by addition):