\section{HILBERT Hilbert Transform}

\subsection{Usage}

The \verb|hilbert| function computes the hilbert transform of the argument
vector or matrix.  The FreeMat \verb|hilbert| function is compatible with
the one from the MATLAB API.  This means that the output of the
\verb|hilbert| function is the sum of the original function and an
imaginary signal containing the Hilbert transform of it.  There are
two syntaxes for the hilbert function.  The first is
\begin{verbatim}
  y = hilbert(x)
\end{verbatim}
where \verb|x| is real vector or matrix.  If \verb|x| is a matrix, then he
Hilbert transform is computed along the columns of \verb|x|.
