Estimation of frequency, amplitude, and phase from the DFT of a time series

In a previous paper, a frequency estimator using only three Fourier coefficients was introduced, which has asymptotic variance of order T/sup -3/. In this correspondence, a similar technique of Rife and Vincent (1970) is shown to have asymptotic variance of larger order. A new estimator is introduced that has asymptotic variance Less than 1.65 times the CRLB.