t;nrise&gt &lt;ncut&gt &lt;width&gt boxcar</kbd>
<li> <b>Voigt filter:</b>    <kbd>filter &lt;nrise&gt &lt;ncut&gt &lt;ampnoise&gt voigt</kbd>
</ul>

These four forms of the filter command invoke different types of filters (see below).
The meaning of the command parameters is:

<dl>
<dt> <b>nrise</b>
<dd> rise width of cosine bell to avoid end effects<p>

<dt> <b>ncut</b>
<dd> cut off frequency of the FFT<p>

<dt> <b>ampnoise</b>
<dd> magnitude of the transform at the cutoff frequency <b>ncut</b>
     of th