4.12  SIN: Sinusoidal time dependent value

4.12.1  Syntax

SIN args
SIN offset amplitude frequency delay damping

4.12.2  Purpose

The component value is a sinusoidal function of time, with optional exponential decay.


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

It generates either a steady sinusoid, or a damped sinusoid.

If delay and damping are both zero, you get a steady sine wave at the specified frequency. Otherwise, you get a damped pulsed sine wave, starting after delay and damping out with a time constant of 1/damping.

The shape of the waveform is described by the following algorithm:
reltime = time - _delay
if (reltime > 0.){
  ev = _amplitude * sin(2*PI*_freq*reltime);
  if (_damping != 0.){
    ev *= exp(-reltime*_damping);
  ev += _offset;
  ev = _offset;
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.

4.12.4  Parameters

Offset = x
DC offset. (Default = 0.)

Amplitude = x
Peak amplitude. (Default = 1.)

Frequency = x
Frequency, Hz. (required)

Delay = x
Turn on delay, seconds. (Default = 0.)

Damping = x
Damping factor, 1/seconds. (Default = 0.)