National Instruments 370757C-01 用户手册

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Using this relation and any of the previously discussed approximations for 
μ(

.

), you can compute an approximation to 

wcgain( )

. Because the 

approximations to 

μ(

.

) are upper bounds, the resulting approximations to 

wcgain( )

 also are upper bounds. For speed purposes, 

wcgain( )

 uses 

Perron-Frobenius scaling to calculate the approximation of 

μ. 

gamma = wcgain(H, gammin, gammax, gam0)

The 

wcgain( )

 function estimates the largest possible magnitude from 

a given input of the system to a given output, when the other inputs are 
connected to the other outputs through uncertain transfer functions 
bounded by one. 

For a discussion of 

wcgain( )

 syntax, refer to the Xmath Help. This is a 

low-level function that calculates the worst-case gain at a single frequency, 
where the magnitude bounds are normalized to one as follows:

Because it is a lower level function, there is no syntax checking. This 
function is called by the 

wcbode( )

 function.

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