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500 MHz LUMPED ELEMENT FILTER
This project shows a Lumped Element Filter. The optimizer has been used to produce the required element values for the correct frequency performance. The element values are tunable and can also be adjusted real time by clicking on the tuning slider icon.
Within this project is one schematic design, "LPF". Using lumped, ideal elements, the filter topology is entered and the values set to be optimizable and tunable.
This can be achieved by selecting each element in turn with a double left mouse click and changing the element parameters. For access to more than one element at a time, choose Simulate > Optimize on the menu. In the Optimizer dialog box, the bottom left Variables icon gives access to the project variables. Columns can be sorted by clicking on the column heading, and extra columns can be added by right clicking on the heading bar. All seven values for the element fundamental properties are set to be optimizable. A constrained (or limited) range is recommended, even if it is extreme, to avoid the optimizer taking the value to zero or infinity.
The optimizer goals are added from the project tree by right clicking on the "Optimizer Goals" branch. The user can choose from any rectangular or tabular graph measurement (already plotted in the project) from the list offered. The number of goals that can be set is unlimited, and each is color coded with the trace it accompanies. Once on the graph, the goals can be dragged around graphically within the graph itself. Differing weights (or importance) can be set with each goal, such as making insertion loss 5 times more important in this example.
Modeling and Simulation
In this filter, more realistic inductors have been used with resonant frequencies. If this design were to be laid out onto a board, parasitics of the bonding pads would also need to be taken into account.
For further help on the use of the optimizers and the method available, please see the Optimizing, Tuning, and Yield chapter of the User's Guide.