Improving performance of digital sinusoidal oscillators by means of error feedback circuits

A method is presented in which an addition of an error feedback circuit to a direct form digital oscillator considerably reduces the roundoff errors. Formulas for the variance of the output roundoff error are derived for the direct form digital oscillator without error feedback, and with first-and second-order error feedbacks, and the reduction in noise power due to error feedback is demonstrated. Simulation results are given showing that both the frequency and the amplitude of the generated waveform are very close to the ideal case.