oise jamming is examined to illustrate our general coded error bound evaluation. Assume a jammer with power J that transmits Gaussian noise with con- stant power spectral density over a total bandwidth W. This jammed band- width is some subset of the total FH/MFSK signal bandwidth Wss and it is assumed that the transmitter and receiver do not know this jammed band- width before transmission. Indeed, the jammed subset of total bandwidth W1 may be changed randomly by the jammer to prevent the transmitter and receiver from knowing what frequencies will be jammed. The fraction of the jammed band is denoted (4.82) Thus, defining N1 = J/W ss, the true noise power spectral density is (4.83) for W1 Hz and zero for the rest of the spread bandwidth. Assuming that an MFSK signal is transmitted during the time interval of Ts seconds, the hop time interval is denoted Th seconds, then Th=dTs (4.84) where d is a fraction or a positive integer. Thus, there are d MFSK symbols transmitted during each hop interval.³ Assume that each hop is independent of other hops and equally likely to be in any part of the total spread-spec- trum signal frequency band of Wss Hz. Thus, the probability of transmitting an FH/MFSK symbol in a jammed frequency band is given by p. Throughout this analysis, also assume that (4.85) SO that during any hop interval the whole set of M possible tones is either totally in the jammed band or not. This ignores the unlikely cases where the M possible tones straddle the edge of the jammed band leaving only some of the M tone positions with jamming noise present. When (4.85) holds, this edge effect can be ignored. SLater in the text, we refer to the case where d>1 as slow frequency hopping (SFH) and d < 1 as fast frequency hopping (FFH). General Analysis of Anti-Jam Communication Systems As always, ideal interleaving is assumed SO that the coding channel is mem- oryless (see Part 1, Chapter 3, Section 3.8). In this FH/MFSK example, it means that each transmitted M-ary symbol is jammed with probability p and not ja