Mean Time to Lose Lock for the “Langevin”-Type Delay-Locked Loop

The classical result of Kramers, originally related to chemical reaction rates, is applied in this letter to a second-order all-pole, coherent code tracking delay-locked loop (DLL). A very simple, explicit expression for the leading order term of the mean time to lose lock (MTLL) is presented. The dependence of the MTLL on the loop tension (offset) due to Doppler shift and code clock mismatch is given, and optimal loop parameters which maximize the MTLL are proposed.