 1976. [37] L. B. Milstein and P.K. Das, "Spread spectrum receiver using surface acoustic wave technology," IEEE Trans. Commun., COM-25, No. 8, pp. 841-847, August 1977. Pseudonoise Code Acquisition in Direct-Sequence Receivers [38] A. Polydoros, "On the synchronization aspects of direct-sequence spread spec- trum systems," Ph.D. Dissertation, Department of Electrical Engineering, University of Southern California, August 1982. [39] A. Polydoros, and M.K. Simon, "Generalized serial search code acquisition: The equivalent circular state diagram approach," IEEE Trans. Commun., COM-32, pp. 1260-1268, December 1984. Chapter Chapter 2 PSEUDONOISE CODE TRACKING IN DIRECT-SEQUENCE RECEIVERS In the previous chapter, we discussed techniques for acquiring a pseudonoise (PN) code in direct-sequence (DS) spread-spectrum (SS) receivers. Although PN acquisition is an extremely important problem, e.g., the code must cus- tomarily be acquired in as short a time as possible, the development of closed loop techniques for accurate PN tracking plays an equally important role in supporting the acquisition process once the code has been acquired. As such, the optimum design and true assessment of the performance of the PN track- ing loop is an essential component of the overall receiver design. In searching the literature, one finds that over the years there have been predominantly two PN tracking loop configurations that have been proposed and analyzed, namely, the delay-locked loop (DLL) [1]-[5] and the tau-dither loop (TDL) or time-shared loop [5]-[7]. Either of these configurations can be operated in a coherent or non-coherent mode depending on the system application. Furthermore, both of them fall within the class of so-called early- late gate type loops in that the received PN code is correlated either simul- taneously or alternately with delayed and advanced versions of the receiver local code PN generator output to produce the timing error correcting char- acteristic. More recently, modifications of the basic TDL and DLL, name