bstap hankel approximant

## Syntax

    Q = bstap(Sl)

## Arguments

sl

  linear system (`syslin` list) assumed continuous-time and anti-stable.

Q

  best stable approximation of `Sl` (`syslin` list).

## Description

Computes the best approximant `Q` of the linear system `Sl`

where

||T||

is the H-infinity norm of the Hankel operator associated with `Sl`.

## See also

- syslin