Variable Step Size Adaptive Sub-Sample Delay Estimation Using a Quadrature Phase Detector

A new adaptive delay estimation algorithm with variable step size based upon a quadrature phase detector and a fractional delay filter (FDF) is introduced. The estimator improves the convergence rate of the recently proposed adaptive quadrature delay estimator (QDE). This convergence parameter is a function of the phase error. Simulation results verify the improved performance in terms of convergence rate and stability, especially when the convergence factor mu is small and SNR is low.