Using The Expression Builder

The Expression Builder, shown in Expression Builder Window, is used to create expressions to perform detailed analysis of simulation data. The waveforms produced by the expressions can be displayed in the Results Display window.

Figure 6-1: Expression Builder Window

Expressions can be created by typing the expression directly into the expression field, or they can be created by making selections in the desired order from the lists of available functions, waveforms, operators, macros, and other expressions.

Using Functions

The Functions list shows the functions that are available for use in creating expressions and macros. These are predefined functions. The functions available in AvanWaves are defined in Appendix B.

To use a function in an expression:

1. Select the function from the Functions list, then drag it into the Expression field. Alternatively, double-click on the function to insert it into the Expression field at the current cursor location. You can place the cursor by clicking at the desired insertion location.

2. Enter the arguments for the function either manually or by selecting and dragging curves from the Results Browser.

If a function takes two arguments, you can select both values for these arguments from the Results Browser and drag them to the Expression field together. Each curve entered as an argument is prefixed with its design and analysis number.

All functions work on either constants or waveforms. If a function is applied with one argument that is a constant and one argument that is a waveform, the constant is changed into a "constant value" waveform, and then the operation is performed.

Functions and Expressions can contain arguments that have not yet been defined. A function must have at least one argument, and not more than two. The expression name must be unique.

Using Operators

A set of arithmetic, numeric comparison, Boolean, and conditional operators are available for use in building expressions and macros in the Expression Builder. The following are the types of operators that can be selected from the Operators list:

• Arithmetic (+, -, *, /) -- return analog waveforms only
• Comparison (>, <, <=, >=, !=, ==) -- return logical waveform results (1 or 0)
• Boolean combination ( &&, ||, !) -- return logical waveform results (1 or 0)
• Conditional (expr1 ? expr2 : exp3) -- analog wave built from expr2 if expr1=0 or expr3 if expr1 is not equal to 0

To use an operator in an expression:

1. Place the cursor in the expression where you want to enter the operator.

2. Select the operator from the Operators list.

3. Click on the operator and drag it into the Expression field.

Using Curves in Expressions

Any curve (simulation waveform) can be placed in an algebraic expression as a parameter. The result of the expression operating on the waveform then can be displayed as a new waveform.

To use a waveform as a parameter in an expression :

1. Select the function to use.

2. Select the waveform.

Selecting and Editing Expressions

To select an existing expression:

1. Click Clear . This clears the Expressions field.

2. With the left mouse button, double-click on the expression (result name) in the Expressions list.

To edit the definition of an expression:

1. Select the expression.

2. In the Expression field, modify the expression definition, then click Apply .

Using Expressions

The Expressions list contains all the expressions created in AvanWaves using the Expression Builder. The expressions are saved with the current designs when a configuration is created. An expression can be used as part of another expression by selecting it and dragging it into the Expression field.

To add an expression to the Expressions list:

1. Enter an expression in the Expression text entry field, and enter a name for the result in the Result field.

2. Click Apply or press Return to enter the expression in the Expressions list.

To expand an expression to display its definition: