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Project Options Dialog Box: Interpolation/Passivity Tab

The Project Options dialog box Interpolation/Passivity tab allows you to specify interpolation options for the simulations performed in this project. To access this tab, choose Options > Project Options or double-click Project Options in the Project Browser. This dialog box contains the following options:

Field Description
Interpolation Options Choose one of the following interpolation methods:
Linear: Uses a linear function to interpolate between points.
Rational Function: Use rational functions to interpolate between points (for example, smoothing). Missing data points are estimated by fitting a pole-zero model to the points used for the interpolation. The pole-zero model of the data can accurately represent the transfer function of measurements taken on physical devices (such as the S-parameters of a passive component).
Spline Curve: Uses a spline curve to interpolate between points.
Rational Function

Window Size: Determines the maximum number of frequency points used to compute the interpolated data. If the window size is larger than the number of frequency points in the data file, the window size is automatically set to the number of frequency points in the data file. Set this option to specify the maximum number of frequency points to use to compute the interpolated data. The following figure demonstrates the operation of the window. Each tick on the line represents a frequency point in the data file. The bold tick marks represent the points that would be used to interpolate the indicated point if a window size of 4 is selected. The window slides along the axis as the interpolation point changes. A larger window size includes more points in the interpolation, but the simulation is slower.

Spline Curve Options Spline Order: Specify the spline order.
Coordinate System Cartesian: Interpolates complex numbers by interpolating their real and imaginary parts.
Polar: Interpolates complex numbers by interpolating their magnitude and unwrapped phase.
MDIF and Load Pull Files Align gammas over power: Interpolates the load pull A and B values to keep the gammas fixes over swept power. The default is off.
Block name: Specifies the data block within the MDIF document to use when there is more than one data block available. If there is only one data block, or for load pull documents where the data blocks are known (for example, HEADER and ABWAVES blocks are present), leave this blank unless you want to read values from the HEADER block using one of the functions for reading generalized MDIF. In this case you need to create a copy of the MDIF document and set this value to HEADER. Load pull deembeding structure: Specifies the two port network (circuit schematic, data file, or EM structure) used to deembed the output pin of load pull data (move the reference plane of the output measurements from the device pin to the other side of the specified network).
EM Documents and Data Files Consider Passive for Noise Simulation: Noise is calculated different for network parameters (S-parameters, etc.) if the network is passive or active. This can occur if there is calibration error in measurement or numerical error in EM simulation causing a passive structure to be slightly active. This option forces the structures noise to be calculated using the passive method. This option can be set globally or per data file or EM document.
Enable parameter interpolation: Allows parameter interpolation for any numeric VAR values (unless your VAR type is a string).

NOTE: Interpolation must be used carefully. Always visually check the results of the interpolation to make sure it did not break down at any point. For example, if the data is noisy, the interpolation may not provide the desired results. If it appears that the interpolation has failed to provide reliable results, try increasing or decreasing the window size in this dialog box.

Interpolation/Passivity tab settings do not apply to the interpolation of the parameter values for MDIF N-Port file format and EM data sets resulting from SWPVAR simulations. Interpolation of parameter values uses the Linear method and Cartesian coordinate system.

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