lar, for the special case of partial-band noise with spectral fill factor p, (2.130) is modified by the addition of the familiar factor of 1/2 (refer to [10] and Appendix 2A): Pb=1/G(D); noise jamming (2.131) and, for the soft decision linear combining metric with perfect side infor- mation (see (4.92), Volume I), (2.132) where The parameter EJN, is the MFSK chip energy-to-jamming noise spectral Non-Coherent Frequency-Hopped Systems power ratio (see (4.2), Volume I): (2.133) where R is the code rate expressed in information bits/chip. Recall that the transmission of a chip represents a single use of the M-ary channel; a chip is an M-ary symbol from the innermost code. For example, in an uncoded system with diversity m (we could also regard this as a simple repetition code as discussed previously), each diversity transmission is a single M-ary chip and R = Klm. For worst case partial-band noise [5], we want to maximize D over p E (0,1]: (2.134) while for EJN, < 3, D is given by (2.132) with p = Pwc=1. For multitone jamming, the Pb bound of (2.130) must be used. For n = 1 band multitone jamming, the performance bounds have the form (refer to (2.75), (2.86), and (2.87)) (2.135) Referring to the definition of D in (4.20) in Volume I, we see that D is sim- ply equal to F, with KEm replaced by EJN, In terms of the jammer power parameter a, which is restricted to the range (see (2.89)) 0<a<min(1-MN,) (2.136) we have K = 1 (2.137) K 2 2. Maximizing D over a for worst case n = 1 band multitone jamming, for the special case K = 1, (2.138) Coding Countermeasures Similarly, for K 2 2, (2.139) where B and ao are given in Table 2.7 for 2 V K V 5. We now want to specify G(D) for the codes of interest in this section. As a reference point, for the m-diversity repetition code (see (2.62)), G(D)==="D" and R= K = m (2.140) In worst case partial-band noise, the diversity that minimizes Dm (the so- called quasi-optimum diversity that minimizes the bound on Pb in [2]) is given by (see (2.70)) (2.141) Combining (2.131), (2.133), (2.134