Median filters

Syntax: | `FILTER x f npt FILTER\MEDIAN x f npt`

The default is `\MEDIAN`, that is, to use a running median filter. The data array, `x`, is filtered through a window `npt` points in width. `npt` must be `>2`.

The median filter is particularly good at removing 'spikes' from data. The median filter moves a window over the data and outputs the median value of the data points within each window placement. The window butts up against the ends. When `npt` is even, the filter is applied twice, first skewed left then skewed right, and the results are averaged.

FILTER command
Mean filters