Abstract
In this paper, a single-input single-output linear discrete time model reference adaptive control problem is considered. By transforming the systems description of both the model and the plant into the systems description whose state variables are all known, a very simple adaptive system which uses only accessible signals can be constructed. Further, it has been revealed that an adaptive scheme can be obtained easily by introducing additional filters developed by the authors, even if the difference between the degrees of the denominator and numerator polynomials of the plant transfer function is greater than two.