Plot worst-case gain of uncertain system

`wcsigma(usys)`

`wcsigma(usys,w)`

`wcsigma(___,opts)`

`wcsigma(`

plots
the nominal and worst-case gains of the uncertain system `usys`

)`usys`

as
a function of frequency. For multi-input, multi-output (MIMO) systems,
gain refers to the largest singular value of the frequency response
matrix. (See `sigma`

for more
information about singular values.) The plot includes:

Nominal — Nominal gain of

`usys`

.Worst — The response falling within the uncertainty of

`usys`

that has the highest peak gain.Worst-case gain (lower bound) — The lowest possible worst-case gain at each frequency.

Worst-case gain (upper bound) — The highest possible gain within the uncertainty at each frequency. This curve represents the envelope produced by finding the highest possible gain at each frequency.

Sampled Uncertainty — 20 responses randomly sampled from

`usys`

.

`wcsigma`

uses `wcgain`

to
compute the worst-case gains. Use the `opts`

argument
to set options for the `wcgain`

algorithm.

`wcsigma`

uses `usample`

to compute the ```
Sampled
Uncertainty
```

curves.