 0, +2, 44...., +(K-2). It is of interest to evaluate the limit of Ps of (2.103) as EIN approaches 80). From (2.93), we first note that lim = 8 B->00 lim = A1 sin OJ + j cos 01 - i sin AJ. (2.106) B->00 Performance of FH/DQASK in the Presence of Partial-Band Multitone Jamming Then, substituting (2.106) into (2.105) and simplifying gives B->00 ass sin OJ + m(1 - l)cos 0J + (2.107) which when averaged over 01 results in 15 independent of A, (2.108) Thus, applying (2.108) to (2.103) gives the final desired result, namely, lim = (2.109) TONE JAMMING NOISE JAMMING Ppmax FH/DPSK-16 FH/DQASK-16 Eb/Nj,db Figure 2.14. Worst case P versus EIN, for FH/DQASK-16 and FH/DPSK-16. Differentially Coherent Modulation Techniques Finally, using the same relation between average symbol and bit error probabilities as for FH/MDPSK, namely (2.15), then the worst case jamming strategy for FH/DQASK-16 can be determined to be Eb/NJ (2.110) Eb/N J < 2.4 (2.111) where Pslp=1 is given by (2.103) with p = 1. Figure 2.14 illustrates this worst case jammer bit error probability performance. 2.5 PERFORMANCE OF FH/DQASK IN THE PRESENCE OF PARTIAL-BAND NOISE JAMMING Since we are ignoring the background AWGN, the results for the perfor- mance in the presence of a partial-band noise jammer are then directly obtained from the Gaussian results in Section 2.3 by replacing No with Nj/p. In particular, the average symbol error probability performance is given by (2.80), multiplied by p, namely (2.112) where the dependence of the integrand on p is entirely contained within the parameter A of (2.75) which now becomes (2.113) Once again using (2.15) to obtain Pb from Ps, we obtain the worst case jam- mer performance given by (2.114) Eb/N1 5.0 (2.115) Eb/NJ References where now Pslp=1 corresponds to (2.112) with p = 1. The behavior of Phmax of (2.115) as a function of EIN, in dB is also illustrated in Figure 2.14. Finally, for the purpose of comparison, the results of (2.43) and (2.50), cor- responding to the worst case tone and noise jammer performances of F