NMRPipe Processing Functions
SMO: NPoint Smoothing.

The SMO function performs smoothing or centering on data vectors. If the current dimension is complex, the real and imaginary parts of each vector are treated separately. In smoothing, a given point in the data vector is replaced by the local average of all points in the range +/ N points away. This means that a given local region in the interior of the vector will consist of 2*N + 1 points, but fewer points at the head and tail of the vector.
OPTIONS
n N
This option specifies N, the +/ size of the local region used
for the calculation. The value can be specified with units of
Pts Hz ppm %, but will be rounded to an integer number of points.
center
If this flag is used, centering will be performed instead of
smoothing. In centering, the local average is subtracted
from each point.