The Triangle filter option in the Construct Filter Feature dialog box (Insert | Feature | Constructed | Filter) filters the data by a weighted moving average of all the points in a moving window. The weights are determined by a triangle function with the peak in the middle of the window. You can specify the width of the window through either the Smoothing parameter or the Filter width value.
If the Filter width is m then the window is 2m·* delta wide, where delta is the point spacing.