Effects of jitter and cycle slipping of phase reference upon unique word missed detection in QPSK systems

The paper examines the effects of phase jitter and cycle slipping of the recovered carrier on the unique word (UW) missed detection in coherent QPSK satellite communications systems. The fluctuation nature of the recovered carrier phase is examined, and it is found that the phase fluctuates very little during the UW period. It is shown that the UW is undetectable even in DCPSK if a cycle slip occurs in the UW period, and an expression of the UW missed detection probability (UWMP) due to the recovered carrier cycle slipping is presented. In addition, the critical fact was disclosed that the bottoming effect occurs in the UWMP characteristic with the increase of UW length; hence, the increase of UW length is not always an effective method for gaining better UW missed detection performance.