Display transfer function on masked subsystem icon
dpoly(num,den) dpoly(num,den,'character')
dpoly( displays
the transfer function whose numerator is num, den)num and
denominator is den.
dpoly( specifies
the name of the transfer function independent variable. The default
is s.num, den, 'character')
When Simulink® draws the block icon, the initialization commands execute and the resulting equation appears on the block icon, as in the following examples:
To display a continuous transfer function in descending powers of s, enter
dpoly(num, den)
For example, for num = [0 0 1]; and den
= [1 2 1] the icon looks like:

To display a discrete transfer function in descending powers of z, enter
dpoly(num, den, 'z')
For example, for num = [0 0 1]; and den
= [1 2 1]; the icon looks like:

To display a discrete transfer function in ascending powers of 1/z, enter
dpoly(num, den, 'z-')
For example, for num and den as
defined previously, the icon looks like:

If the parameters are not defined or have no values when you
create the icon, Simulink software displays three question marks
(? ? ?) in the icon. When you define parameter
values in the Mask Settings dialog box, Simulink software evaluates
the transfer function and displays the resulting equation in the icon.
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