f <code>i</code> is <code>"u1"</code> then the return value is <code>v[,1]</code>. The
same holds for 2, etc., depending on the number of beams in
the instrument.</p></li>
<li><p>If <code>i</code> is <code>"a1"</code> then signal amplitude is returned, and similarly
for other digits. The results can be in <code><a href="https://rdrr.io/r/base/raw.html" class="external-link">raw()</a></code> or numeric form,
as shown in the examples.</p></li>
<li><p>If <code>i</code> is <code>"q1"</code> then signal quality 