Robust Hyperbolic Sigma-Delta Based No Delay Tanlock Loop for Wireless Communications

This paper presents a new fast locking phase lock loop architecture for frequency synchronization and tracking. The proposed Hyperbolic Σ-Δ No Delay Tanlock Loop (NDTL) has an extended lock-in range and an improved time jitter. The loop has an intentionally introduced hyperbolic nonlinearity, modified Σ-Δ blocks, and finite state machine (FSM), to adapt the loop filter, extending the locking range and improving the timing jitter. The proposed hyperbolic NDTL architecture performs well even in wireless communication systems with high Doppler shift (e.g. vehicular communications) that might cause the system to lose stability. The simulation results under various test scenarios demonstrate that the new architecture offers robust performance in terms of lock-in range, acquisition time, and timing jitter.