This page can be found on the Define Source dialog.

Use it to directly define the SPICE command for a Source device. For example a Piece Wise Linear Source, Exponential Source or a Single Frequency FM Source.

Shortcuts

Default Keys: F7

Command: Edit Spice Value/Model

How To Define A Source’s Signal

Use the Define Source dialog to edit a source device. Click on the Other tab.

The following dialog will be displayed:

This is used to enter stimulus sources not directly supported by other source pages. Here, the raw text command to specify a source can be entered.

The following three source commands can be specified:-

Piece Wise Linear Source

pwl ( T1 V1 [T2 V2 [T3 V3 [… ]]] )

Each pair of values (Ti Vi) specifies that the value of the source is Vi at time = Ti. The value of the source at intermediate values of time is determined by using linear interpolation on the input values.

Exponential Source

exp ( V1 V2 [TD1 [TAU1 [TD2 [TAU2 ]]]] )

where:

V1�������Initial value (Volts or amps).

V2�������Pulsed value (Volts or amps).

TD1�����Rise delay time. Default if omitted is zero.

TAU1���Rise time constant. Default if omitted or zero is the Time step.

TD2�����Fall delay time. Default if omitted or zero is TD1 + Time step.

TAU2���Fall time constant. Default if omitted or zero is the Time step.

The Time step is specified in the Transient Analysis.

Single Frequency FM Source

sffm ( VO VA [FC [MDI [FS ]]] )

Defined by:

V(t) = VO + VA.sin[2.p.FC.t+MDI.sin(2.p.FS.t)]

where:

VO�����Offset (Volts or amps).

VA������Amplitude (Volts or amps).

FC�����Carrier frequency (Hz). Default if omitted or zero is 1/Stop time.

MDI����Modulation index. Default if omitted is 0.

FS������Signal frequency (Hz). Default if omitted or zero is 1/Stop time.

The Stop time is the end time of the Transient Analysis.

Editing Multiple Components

If the description is set to then some of the components you are changing have different source descriptions. Clear this field and enter the required value for all components, or leave as to tell components to keep their original descriptions.

Define Source | AC Source | DC Source | Edit Device Type | Noise Source | Pulse Source | Sine Source | Transient Analysis