Impact of unknown offset in amplitude estimation of a digitized sine wave

This work deals with the characterization of the uncertainty in the estimation of the amplitude of a sine wave with unknown offset through the discrete Fourier transform. Starting from the application of the analytical model of quantization, it is shown that the conventional noise model of quantization in this case can lead to an underestimation of the uncertainty. Moreover, it is shown that by introducing additive noise with increasing level, the effect of unknown offset is progressively masked. The proposed results are validated by means of numerical simulations. The topic has specific significance in applications based on high-speed low-resolution ADCs, where quantization is a significant source of uncertainty.