Abstract: A method and apparatus for controlling an equalizer receiving the output of an unknown system in order to produce a desired response for recovering the input to the system are characterized by iteratively adjusting the equalizer such that the unknown system combined with the equalizer behaves essentially as a linear system whose (t,n) taps, for some combinations of t and n, are iteratively adjusted according to the following rule: ##EQU1## where s.sub.t,n denotes the (t,n) tap before the iteration, s'.sub.t,n denotes the (t,n) tap after the iteration, I is a preselected integer greater then or equal to one, .alpha..sub.i i=1,2 . . . I are preselected scalars that may vary from iteration to iteration, and p.sub.i, q.sub.i i=1,2, . . . I are preselected non-negative integers such that p.sub.i +q.sub.i .gtoreq.2.