The basic DDS relies on the behavior of an overflowing accumulator to establish the output frequency of the DDS. The behavior of the accumulator exhibits two beneficial features. First, it generates a repetitive numeric sequence uniformly separated in time by a fixed interval, namely the period of the system clock. Secondly, it provides numeric control of the step size between adjacent values in the repeating numeric sequence, the step size being the value of the FTW. The ability to control the step size directly controls the overflow period of the accumulator, which ultimately establishes the frequency of the DDS output sinusoid.