Block time delay estimation by Newton´s method with allpass constraints

Time delay estimation (TDE) is an important procedure for many communications and signal processing tasks. In this paper, a novel TDE algorithm is proposed. The block-based method estimates the phase response of a sine-interpolation filter using Newton´s method on the space of allpass filters, from which the delay estimate is calculated using a simple coefficient-based formula. The algorithm is amenable to fast convolution procedures and needs only a few iterations to converge. Simulations comparing the proposed method with the well-known linear phase and time-domain cross-correlation methods show that our technique achieves a lower mean-squared error than these other methods in low signal-to-noise ratio environments.