The table referenced must be specified in the input deck with a .table line. The reference to a table is in the form of a table function, as above, which takes two arguments. The first argument is the name of a table defined elsewhere in the circuit file with a .table line. The second argument is an expression which provides input to the table. The return value is the interpolated value from the table.
Tables can also be referenced as part of the ac specification for a dependent or independent source. These references are used in ac analysis, and have a different referencing syntax.
In the expression used in voltage and current sources, dependent and independent, the second form can be used and is equivalent. The table_name must not conflict with another internal or user-defined function name.
The table reference provides one means of implementing a piecewise-linear transfer function. This can also be accomplished by use of the pwl function in dependent sources.