 fraction of the band jammed, which is given by p = cannot exceed one, the value B = 0.52 can only be achieved if EbIN1 > 1.85. For smaller values of E/N, the relation B = 1/V2Eb/N , must be used. Thus, we arrive at the following corrected results for M = 4. Eb/N,> 1.85 Eb/NJ Eb/N1 < 0.5 Performance of FH/MDPSK in the Presence of Partial-Band Multitone Jamming E /N, ,BB , Figure 2.6. Worst case bit error probability performance of FH/MDPSK for partial- band multitone jamming. jumps from .4375 to .5. For other values of M 4, a similar jump disconti- nuity in the worst case tone jammer bit error probability will occur at B = 1 and p = 1, or equivalently, from (2.19), Eb/N1 = 1/logM. Since the range of Eb/N1 in Figure 2.6 extends only down to -2 - dB, these jump discontinu- ities are not visible on this plot, i.e., the largest value of Eb/N, at which a dis- continuity occurs would correspond to M = 4 (E/N, = 1/2 = -3 dB). Differentially Coherent Modulation Techniques 2.2 PERFORMANCE OF FH/MDPSK IN THE PRESENCE OF PARTIAL-BAND NOISE JAMMING The average symbol error probability performance of MDPSK on an AWGN channel is given by [5],[6] (2.45) where Eb/No is the bit energy-to-noise ratio. More recently, the double inte- gral in (2.45) has been shown [7] to be expressible as a single integral, namely, 1 cos t cos (2.46) which lends itself to more convenient numerical evaluation. To obtain the performance of FH/MDPSK in partial-band noise jamming, one has merely to replace Eb/No by pEIN, in (2.46) and multiply the result by p where again p is the partial-band fraction. Thus, also using (2.15), the average bit error probability performance of FH/MDPSK in partial-band noise jamming is given by 1 - cos  cos a (2.47) where (2.48) Performance of FH/MDPSK in the Presence of Partial-Band Noise Jamming Comparing (2.47) with (2.46), we observe that to determine the worst case partial-band noise jammer, one merely uses a tabulation of P (M) versus E/No (or Z), such as that found in Table 5-5 of [5], multiplies these error probabi