Use this when editing a Part to define the Part as a Laplace Transfer device.
Use this on a Laplace Transfer component in a schematic design to change its parameters, or to replace it with a part using a different Laplace Transfer definition.
These parts are implemented by using Functional Modelling. They have their Spice Type Built-in Function set to Laplace Transfer.
Shortcuts
Default Keys: F7
Default Menu: Simulation
Command: Edit Spice Value/Model
How To Add A Laplace Device
There are various ways to add a Laplace Transfer device to a Schematic Design:
- From the Parts toolbar, click on the Analog Behavioural pop-up to display the Analog Behavioural toolbar. Click on the Laplace Transfer button.
- From the Parts Browser, click on Spice Category, then on Analog and Behavioural to display the Analog Behavioural parts. Drag the Laplace Transfer part name into the design. Note: This method may not work if you have changed the part categories.
- Use Component from the Insert menu to add the Part called Laplace Transfer from the SPICE library.
Whichever method is used, you should be presented with the Define Laplace Device Dialog described below. This works because the part named “Laplace Transfer” has a blank function definition which forces the dialog to be given to get the required definition from you.
How To Define a Laplace Transfer
In a Schematic Design, select the Laplace Transfer device(s) that you wish to change. Press F7 or use the Edit Spice Value/Model option from the Simulation menu, or from the shortcut menu.
From a Parts Library edit the required Part. Press the Edit Spice button on the Details tab. Make sure the Built-in Function is set to Laplace Transfer and press the Edit Definition button.
In both cases the following dialog will be displayed:
Definition
Enter an expression using the ‘S’ variable to define the frequency domain transfer function. For example, a second order response would be “1/(S2+1.1*S+1)“.
See the section on Laplace expression in the Simulator Help for more details.
Frequency Scale Factor
Type in the multiplier for the frequency.
Device Type
Choose the type of device:
Transfer Function - Expression defines “Output/Input”
Impedance V/I - Two terminal device, expression defines “Voltage/Current”
Admittance I/V - Two terminal device, expression defines “Current/Voltage”
Input
Choose the input configuration for type Transfer Function.
Output
Choose the output configuration for type Transfer Function.
Changing the Symbol
If editing a Part, make sure the chosen Type, Input and Output values match the Symbol that is used by the Part.
If editing a component in a schematic design, pressing OK with changed Type, Input or Output values will force the component to be replaced with a Part from the Library that matches the new specification. If no suitable Part exists, an error message will be given giving details of the Part that will need to be created.
Editing Multiple Components
If any of the fields are set to
The same applies to Radio Buttons, where no button being set indicates the components have different values for this field.