A new structure digital carrier tracking loop and analysis of its steady-state performance in Z domain

A carrier tracking loop with series-connection structure is proposed to solve the tracking problem of carrier signal. The loop's mathematical phase model is established in Z domain to analyze its dynamic performance and stability. Analytical expressions of the steady-state phase error and stability condition with the loop parameters are obtained. Analysis results show that the loop's dynamic performance is essentially equivalent to a high-order PLL(Phase-Locked-Loop), and the loop's stability condition is easier to be satisfied than the high-order PLL. Numerical simulation results verify the theoretical results. The conclusion can be used to evaluate the receiver's tracking performance or design loop, and also suggests an approach for designing high order PLL.