Digital-PLL Assisted Frequency Estimation With Improved Error Variance

In this paper, the authors present a novel frequency estimation technique, assisted by an imperfect second order arctan based Digital Phase-Locked Loop (D-PLL), for complex single sinusoidal signals in additive white Gaussian noise. The imperfect loop contains the frequency information in its phase error process, at steady state, which is then used to estimate the frequency after the signal has been acquired by the D-PLL. The study of frequency estimation has existed for several decades with applications varying from communications, radar, sonar and many others.