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Where To Find This Example

Select Help > Open Examples... from the menus and type either the example name listed above or one of the keywords below.

Or in Version 14 or higher you can open the project directly from this page using this button. Make sure to select the Enable Guided Help before clicking this button.

Design Notes

500 MHz LUMPED ELEMENT FILTER

This project shows a lumped element filter. This filter is close, but does not meet the difficult to acheive frequency performance goals. The element values are tunable and can be adjusted real time by clicking on the tuning slider toolbar button (or Simulate > Tune menu command).

Overview

There is only one circuit schematic, LPF. Filter schematics can be entered manually, or generated by the iFilter Filter Synthesis wizard. Element parameter values can be set and made optimizable and tunable, as in this example.

Double-click on an individual element to change its element parameters, or choose View > Variable Browser on the menu for access to all variables at once. For more information on using the variable browser, open it and press the F1 key, or choose Help > Knowledge Base to search for "Variable Browser". The fundamental values for all seven elements in the LPF schematic are set to be tunable and optimizable, and are unconstrained. A constrained (or limited) range is recommended, even if it is extreme, to avoid the optimizer taking the value to zero or to an unreasonably large number.

To run the optimizer, choose the menu command Simulate > Optimize , and click the Start button.

Simulation Plots

The optimizer goals are added from the project browser by right clicking on the Optimizer Goals node. The user can choose from the list of previously added measurements in rectangular or tabular graphs. The number of goals that can be set is unlimited. Goals are displayed in rectangular graphs that contain the associated measurements, and are shown in the same color as the measurement trace . These displayed goals can be dragged, or double-clicked and stretched to modify their settings graphically, even while the optimizer is running. A different weight (or importance) can be set with each goal, such as making insertion loss 5 times more important in this example.

Windowed Max to Min Response

Shown in the graph, "Windowed Max to Min Response", are different examples of measuring the peak-to-peak variation over a user defined frequency range. One approach is to use the DMAGB measurement for s-parameter magnitude in dB. Another approach is to use the deltawin() function. Deltawin equations are in Output Equations > Deltawin Equations. The function, deltawin(), allows flexibility in that it can operate on any real data. Shown are examples using s21 magnitude and VSWR.

Additional Information

For further help on the use of the optimizer and optimization methods available, please see our online help: Simulation and Analysis Guide > Simulation Basics > Optimization. For information on the DMAGB measurement, refer to online help: AWR Microwave Office Measurement Catalog > Linear > Change in Magnitude Over a Bandwidth: DMAGB. For information on the deltawin() function, refer to online help: User Guide > Variables and Equations > Equation Syntax > Built-in Functions.

1 Comment

  1. Good description and images.