A Simple Algorithm for Delta Modulators with Delayed Decision

Several different adaptive delta modulator (ADM) algorithms have been described in the literature over the past 15 years. Researchers [1] and [2] have shown that the performance of these algorithms can be improved by using "look ahead encoding" (also referred to as "delayed decision encoding"). In this paper we will present a general technique that can be used with any of these algorithms to effect a one stage look ahead. The technique presented in this paper has the advantage that it does not require the calculation of two encoding paths nor does it require the decision circuitry to choose the optimum path that minimizes a mean square error or absolute error criterion.