 discriminate against versions of the transmitted signal which do not arrive in synchronism with the receiver's clocks. The mean-squared value of the integral in (1.84) is the cross-ambi- guity function of the waveforms mi(t) and MR(t) at offsets t1 and A, and hence, we are embarking on a study of the time- and ensemble-averaged ambigu- ity function provided by an SS waveform/modulation system. The theory of auto-ambiguity functions (i.e., mi(t) = mR(t)) states that the time-width of the function's central and largest peak at t = 0 and A = 0 is inversely pro- portional to the rms bandwidth of the signal upon which the correlator acts. Hence, one might expect under certain conditions that SS receivers are espe- cially sensitive to synchronization errors, and possess high time-of-arrival (TOA) resolution capabilities. The evaluation of (1.84) for repeater modulation of the form (1.83), under the assumption that the added modulation d'(t) is an independent sta- tionary random process, yields mT(t - }r}} (1.85) where Rd() and S&() are the autocorrelation function and PSD, respec- tively, of d'(t); vRj(k) and vm(k) are the values of v1(k) for repeater jamming (1.83) and multipath (1.84) respectively, and (1.86) Henceforth, for simplicity we set (1.87) Equation (1.85) indicates that the effect of the jammer's added modula- tion d'(t) is to average an equivalent multipath interference measure (E{vu(k)2}) at offsets t and f + A over f (weighted by Sa(f)) to determine the repeater jamming measure (E{v M(k)2). A Spread-Spectrum Overview We will now evaluate the multipath interference measure for two basic SS waveform designs. 1. DS/BPSK modulation: In this case mT(t) is given by (1.45) and mR(t) is simply the SS code c(t) in (1.22). Breaking up the integral over the data symbol interval of duration T = Ts in (1.86) into a sum of integrals over the chip intervals of mR(t), gives kNc-1 (n+1)T The integral in (1.88) can be simplified by using the fact that the pulse shape p(t) is non-zero only in (0, Tc) and by defining the q