%$Id: exp.tex,v 21.13 2002/03/25 05:37:03 al Exp $
% man behavior exp .
% Copyright (C) 2001 Albert Davis
% Author: Albert Davis <aldavis@ieee.org>
%
% This file is part of "Gnucap", the Gnu Circuit Analysis Package
%
% This program is free software; you can redistribute it and/or modify
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% any later version.
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% Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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%------------------------------------------------------------------------
\section{{\tt EXP}: Exponential time dependent value}
%------------------------------------------------------------------------
\subsection{Syntax}
\begin{verse}
{\tt EXP} {\it args}\\
{\tt EXP} {\it iv pv td1 tau1 td2 tau2 period}
\end{verse}
%------------------------------------------------------------------------
\subsection{Purpose}

The component value is an exponential function of time.
%------------------------------------------------------------------------
\subsection{Comments}

For voltage and current sources, this is the same as the Spice {\tt
EXP} function, with some extensions.

The shape of the waveform is described by the following algorithm:

\begin{verbatim}
ev = _iv;
for (reltime=time; reltime>=0; reltime-=_period){
  if (reltime > _td1){
    ev += (_pv - _iv) 
          * (1. - Exp(-(reltime-_td1)/_tau1));
  }
  if (reltime > _td2){
    ev += (_iv - _pv) 
          * (1. - Exp(-(reltime-_td2)/_tau2));
  }
}
\end{verbatim}
%------------------------------------------------------------------------
\subsection{Parameters}

\begin{description}

\item[{\tt IV} = {\it x}] Initial value.  (required)

\item[{\tt PV} = {\it x}] Pulsed value.  (required)

\item[{\tt TD1} = {\it x}] Rise time delay.  (Default = 0.)

\item[{\tt TAU1} = {\it x}] Rise time constant.  (Default = 0.)

\item[{\tt TD2} = {\it x}] Fall time delay.  (Default = 0.)

\item[{\tt TAU2} = {\it x}] Fall time constant.  (Default = 0.)

\item[{\tt Period} = {\it x}] Repeat period.  (Default = infinity.)

\end{description}
%------------------------------------------------------------------------
%\subsection{Example} 
%------------------------------------------------------------------------
%------------------------------------------------------------------------
