Determining the optimal coefficients of high-order error feedback

General formulas for the coefficients of Nth-order optimal error feedback (error-spectrum shaping) are derived. It is shown that the optimal error feedback (EF) can be considered to be a special case of Wiener filtering. A fast and accurate algorithm to obtain the optimal coefficients is presented. Explicit formulas for first-, second-, third-, and fourth-order optimal EF coefficients are given.<<ETX>>