Uncertainty Analysis of the RMS Value and Phase in the Frequency Domain by Noncoherent Sampling

The determination of RMS value and phase of harmonic components belongs to the most important tasks of signal analysis in the frequency domain. Evaluation of these parameters is frequently performed using a discrete Fourier transform (DFT) algorithm. In practice, signals are mostly sampled noncoherently. This leads to the well-known effect called leakage, i.e., spreading energy of signal harmonic components into signal frequency neighboring frequency bins. Signals are multiplied by tapering time windows for leakage suppression. This paper is focused on the uncertainty analysis of the RMS value and phase computed from the DFT spectrum of the noncoherently sampled signal using cosine windows. The analysis is focused on investigating the influence of quantization noise.