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Pulse

General Form:
pulse(v1 v2 [td tr tf pw per td1 td2 ... ])
Examples:
vin 3 0 pulse(-1 1 2ns 2ns 2ns 50ns 100ns)
vin1 1 0 pulse(0 1 2n .5n .5n 1n 0 6n 10n)
v2 4 0 v(1)*pulse(0 1 5n 10n)

parameter description default value units
v1 initial value   volts or amps
v2 pulsed value   volts or amps
td delay time 0.0 seconds
tr rise time tstep seconds
tf fall time tstep seconds
pw pulse width tstep seconds
per period tstop seconds

If any of the parameters td1, td2, ... appear, the period is ignored, and the pulse is repeated for the delays td1, etc. The output will be a superposition of these pulses. A single pulse is described by the following table:

time value
0 v1
td v1
td+tr v2
td+tr+pw v2
td+tr+pw+tf v1
tstop v1

Intermediate points are determined by linear interpolation. It is not an error to omit unused parameters, for example the specification

vxx 3 0 pulse(0 1 2n 2n)
describes a voltage which, starting from 0, begins rising at 2 nanoseconds, reaching 1 volt at 4 nanoseconds, and remains at that value.

This function applies only to transient analysis, where time is the running variable. When referring to default values, tstep is the printing increment and tstop is the final time in transient analysis, see 2.7.9 for explanation.


next up previous contents index
Next: Gaussian Pulse Up: Tran Functions Previous: Interpolation   Contents   Index
Stephen R. Whiteley 2017-10-02