The analysis of the performance of a delta modulator with a Wiener process input is considered. The mean and the variance of the steady-state squared error are derived. In addition, the mean of the steady-state error of order four is calculated. It is shown that the behavior of all these moments as functions of the step size Δ and the sampling interval

is similar: for each fixed Δ, the moments are monotonically increasing in

. More important, for each fixed

, there exists an optimal step size Δ
optwhich minimizes each of these moments. It is shown that Δ
optis a multiple of

and that the corresponding minimum value of the moments is a multiple of either

or T
2, depending on the order of the moment.