How about CRLB method? Example:Estimating DC in WGN with unknown variance A (x;A)= 卿{7公-月 0px-司 6A -4∑o网-A+京∑州-A {(1-)∑网-NA+立∑2侧+} whxiong@uestc.edu.cn 5whxiong@uestc.edu.cn 5 = 1 A ½µ 1 ¡ 1 A ¶Xx[n] ¡ NA + 1 2A Xx 2 (n) + N 2 ¾ How about CRLB method? @ ln p(x; A) @A = ¡ N 2A + 1 A X(x[n] ¡ A) + 1 2A2 X(x[n] ¡ A) 2 p(x; A) = 1 (2¼A) N=2 exp ½ ¡ 1 2A ³Xx[n] ¡ A ´2 ¾ Example: Estimating DC in WGN with unknown variance A