9.2.2 Optimum versus Adaptive Filters Optimum filters.If we know the second-order moments of the SOE (Signal operating environment) R(n)c(n)=d(n) (9.2.6) R(n)-E{x(n,)xH(n, (9.2.7) d(n)-E{x(n,y*(n,s (9.2.8) Wiener-Hopf方程的FIR解Optimum filters. If we know the second-order moments of the SOE （Signal operating environment） 9.2.2 Optimum versus Adaptive Filters Wiener-Hopf 方程的FIR解