Digital sinusoidal oscillator with low and uniform frequency spacing

An extremely low-frequency digital sinusoidal oscillator is proposed and its performance is evaluated. The proposed oscillator structure can generate sinusoidal signals with a large number of samples per cycle without the need for increasing the width of the multiplier coefficient. The difference between two adjacent generated frequencies is shown to be approximately constant over the frequency range of operation. The proposed oscillator utilises one multiple-output direct-form digital oscillator together with very simple shift operations. Simulation results are given to verify the analysis and demonstrate the performance as measured in terms of total harmonic distortion