II. PROPOSED ALGORITHM(2) where X is the original signal, Y is the signal polluted by noise, and N is the noise whose mathematical expectation is zero. The expectation of Y is equal to:and E(Y) can be estimated by the mean of samples of Y. In fact, as (3) shows, as long as the expectation of signal Y tends to be the original signal X, the estimation of X can be got by the mean of samples of Y, though Y has been polluted with noise.