Adaptive second-order TDTL with optimized performance

In this paper the architecture of a second-order time delay digital tanlock loop (TDTL) with real-time adaptive calculation of the loop filter coefficients is proposed. An adaptive digital filter based on the recursive least squares (RLS) algorithm is used to generate the coefficients of the TDTL loop filter. This allows the filter coefficients to be continuously updated in real- time so as to optimise the noise immunity of the TDTL in a highly dynamic environment. The performance of the proposed system was evaluated and compared with the original TDTL system using both additive white Gaussian noise (AWGN) and Doppler shifts. The results indicate that the noise performance of the proposed system outperforms that of the original TDTL.