On the identification of discrete-time systems via discrete orthogonal functions

This paper deals with the identification of three classes of (linear time-invariant, time-varying, and nonlinear) discrete-time systems via discrete orthogonal functions (DOFs). The important results of this study are as follows. (1) The new discrete-pulse orthogonal functions (DPOFs) approach is much simpler than that of Horng and Ho (1987). (2) The identification algorithms derived via DPOFs are computationally the simplest of all the algorithms developed via discrete Laguerre polynomials (DLPs), or discrete Legendre orthogonal polynomials (DLOPs). (3) The DPOF-based algorithms and the standard well known least squares algorithms are identically one and the same for discrete-time system identification. In view of points (2) and (3), it is concluded that the DOF approach for system identification is not an attractive approach computationally. (C) 1998 Elsevier Science Ltd.