====== "pulse" Pulsed time dependent value ======

===== Syntax =====

  pulse args
  pulse iv pv delay rise fall width period

===== Purpose =====

The component value is a pulsed function of time.

===== Comments =====

For voltage and current sources, this is the same as the Spice "pulse" function, with some extensions.

The shape of a single pulse is described by the following algorithm:

<code>
if (time > _delay+_rise+_width+_fall){
  // past pulse
  ev = _iv;
}else if (time > _delay+_rise+_width){
  // falling
  interp=(time-(_delay+_rise+_width))/_fall;
  ev = _pv + interp * (_iv - _pv);
}else if (time > _delay+_rise){
  // pulsed value
  ev = _pv;
}else if (time > _delay){
  // rising
  interp = (time - _delay) / _rise;
  ev = _iv + interp * (_pv - _iv);
}else{
  // initial value
  ev = _iv;
}
</code>

For other components, it gives a time dependent value.

As an extension beyond Spice, you may specify the parameters as
name=value pairs in any order.
===== Parameters =====

|iv      |Initial value.  (required)  |
|pv      |Pulsed value.  (required)  |
|delay   |Rise time delay, seconds.  (Default = 0.)  |
|rise    |Rise time, seconds.  (Default = 0.)  |
|fall    |Fall time, seconds.  (Default = 0.)  |
|width   |Pulse width, seconds.  (Default = 0.)  |
|period  |Repeat period, seconds.  (Default = infinity.)  |
===== Step control =====

The corners in a pulse waveform are considered to be analog events.  The transient analysis will attempt to control timing accuracy of these analog events.  If it is reasonable, a time step should be scheduled at these times exactly.  In any case, there should be a time step within option::dtmin of these times.