Tradeoffs between Timing Jitter and Mean-Time-to-Lose-Lock in DLL Code Tracking of CDMA Signals

摘要

This paper explores the tradeoffs between tracking jitter and mean-time-to-lose-lock (MATTL) of the delay lock loop (DLL) circuit used in code tracking of direct-sequence spread-spectrum (DS/SS) systems. Several families of chip waveform pulses are considered. New results are presented to show that the DLL performance can be optimized by using proper pulse shaping and early-late delay lock loop spacing in a way to achieve a low code residual tracking jitter and a high mean-time-to-lose-lock. Several comparative numerical results are presented in order to illustrate the tradeoffs involved, and to compare the performance of various chip waveform shapes.