Any independent source can be assigned a time-dependent value for transient analysis. The general form of sinusoidal waveform is:



You must specify a value for the parameters VO and VA. the remaining parameters, if not specified, assume a default value.

Parameter Description Units Default
VO DC offset voltage or current. Used to adjust the DC bias of the signal generator with respect to the negative terminal (usually ground). V o A  
VA Peak amplitude of the sinusoid. V o A  
FREQ Frequency of the sinusoidal voltage or current. Hz 1/TSTOP
TD Delay time until the source voltage commences. Provides a phase shift of the output by delaying the start of the sine wave. s 0
THETA Damping factor. Sets the rate at which the sinusoid decreases in amplitude. A positive value results in an exponentially decreasing amplitude; a negative value results in an exponentially increasing amplitude. 1/s 0
PHASE Phase shift of the sinusoid at time zero. degree 0

TSTOP is the final time (see the .TRAN control line for explanation).

The sinusoidal waveform produces an exponentially damped sine wave.

The waveform value generated by the sinusoidal option is as follows:

Time Value
0 to TD VO+VA*sin(2∏*PHASE/360)
TD to TSTOP VO+VA*e-(t-TD)*THETA*sin(2∏*(FREQ*(t-TD)+PHASE/360))


VIN 3 0 SIN(0 1 100MEG 1NS 1E10)

See also

Independent voltage source
Independent current source