An interpolated DFT based on determination of a sampling interval using a virtual synchronous frequency

A new interpolated Discrete Fourier Transform (DFT) based on a sampling interval modification with a virtual synchronous frequency is proposed in this paper. The interpolated DFT is designed for asynchronous sampling which occurs due to lost synchronization with an ADC of a fixed sampling rate under frequency fluctuation. In the explanation of the principle of the interpolation, a sampling number compensation, a rotation factor modification and an integral interval correction (end correction) are described how to contribute to the DFT. It is shown that the amplitude and phase calculation accuracies by using the DFT affect the frequency measurement accuracy.