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Plot passivity of N-by-N rational fit output

Since R2019a



passivity(fit) plots the passivity of the input, fit, over a range of frequencies. Passivity is measured by computing the H-infinity norm of the fit. H-infinity norm is the maximum two-norm of the transfer function H over all the frequencies (0, Inf).

passivity(fit,xlimits) plots the passivity with X-axis limits of the plot.

[maxfreq,maxvalue,freqs,ns] = passivity(fit) returns the data that is used to generate the plot.


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Read the file, passive.s2p and fit the 2-by-2 S-parameters.

S = sparameters('passive.s2p');
fit = rationalfit(S);

Test the passivity of the 2-by-2 fit.

ans = logical

Plot the passivity of the 2-by-2 fit.

passivity(fit,[1e9 40e9])

Figure contains an axes object. The axes object with title Fit not passive, H indexOf infinity baseline blank norm blank is blank 1 blank + blank 1.791e-02 blank at blank 17.6816 blank GHz., xlabel Frequency (GHz), ylabel norm(H) contains 4 objects of type line. One or more of the lines displays its values using only markers

Input Arguments

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Rational fit of S-parameters of passive elements, specified as an N-by-N array of rational or rationalfit object.

Data Types: double

X-axis limits of the plot, specified as a 1-by-2 vector.

Data Types: double

Output Arguments

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Maximum norm(H) over the frequencies (0, Inf), returned as a scalar.

Data Types: double

Frequency at which norm(H) is equal to maximum value, returned as a scalar in hertz.

Data Types: double

Two-norm of the transfer function H, returned as a column vector.

Data Types: double

Frequency values, returned as a column vector.

Data Types: double

Version History

Introduced in R2019a