Design and realization of PN code tracking loop in spread spectrum transponder

PN code phase has been approximately synchronized after PN code acquisition. But code phase is keeping changing constantly under high dynamic environment, and then the correlation peak will be losing lock rapidly if without any compensation approach. Thus how to design code tracking loop under high dynamic environment has become a key step in spread spectrum transponder. This paper begins with the analysis of loop characters, not only derives the sensitivity of phase detector, but also describes the design of loop filter parameters, and at last it gives the simulation results. The analysis and simulation results indicate that it can achieve the goal of accurate tracking of code phase by this kind of code tracking loop.