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Access transfer function data

`[`

returns the numerator and denominator coefficients of the transfer function for the `num`

,`den`

] = tfdata(`sys`

)`tf`

, `ss`

and `zpk`

model objects or the array of model objects represented by
`sys`

.

The outputs `num`

and `den`

are two-dimensional
cell arrays if `sys`

contains a single LTI model. When
`sys`

is an array of models, `num`

and
`den`

are returned as multidimensional cell arrays.

`[`

also returns the uncertainties in the numerator and denominator coefficients of identified
system `num`

,`den`

,`ts`

,`sdnum`

,`sdden`

] = tfdata(`sys`

)`sys`

. `sdnum{i,j}(k)`

is the 1 standard
uncertainty in the value `num{i,j}(k)`

and `sdden{i,j}(k)`

is the 1 standard uncertainty in the value `den{i,j}(k)`

. If
`sys`

does not contain uncertainty information,
`sdnum`

and `sdden`

are empty `[]`

.