Extended tracking range delay-locked loop

In spread spectrum systems PN-code tracking is a crucial performance aspect. The delay-locked loop (DLL) is an appropriate device to guarantee fine synchronization. In this paper, a modified extended tracking range DLL is proposed. In the design of a DLL there is a tradeoff between tracking jitter and tracking range. The loop noise in an extended tracking range DLL is normally increased since more correlators are used. The jitter performance is improved by selecting the two strongest extended DLL branches. This modifies the extended DLL detector S-curve only slightly while reducing the noise power in the loop considerably.