Convert zero-pole-gain filter parameters to transfer function form

`[`

converts a factored transfer function representation`b`

,`a`

] = zp2tf(`z`

,`p`

,`k`

)

$$H(s)=\frac{Z(s)}{P(s)}=k\frac{(s-{z}_{1})(s-{z}_{2})\cdots (s-{z}_{m})}{(s-{p}_{1})(s-{p}_{2})\cdots (s-{p}_{n})}$$

of a single-input/multi-output (SIMO) system to a polynomial transfer function representation

$$\frac{B(s)}{A(s)}=\frac{{b}_{1}{s}^{(n-1)}+\cdots +{b}_{(n-1)}s+{b}_{n}}{{a}_{1}{s}^{(m-1)}+\cdots +{a}_{(m-1)}s+{a}_{m}}.$$

The system is converted to transfer function form using `poly`

with `p`

and the columns of `z`

.