ed by arbitrarily dividing the total signal bandwidth Wss into K contiguous non-overlapping bands. As such, a hit is guaranteed in one of the K channels for each hop. The required per-channel S/N° is given by (1A.1) where the K subscript denotes the per-channel parameters. Now, the term (dknk) is a function of the per-channel PDI and PFAI and the Gaussian assumption correction factor", and WK = WSIK. This leaves only TK to be specified. Clearly, the larger TK is, the lower the (S/No) required. The minimum TK that could be used is TK = Th, the hop pulse period. However, since the indi- vidual channels are, by definition, not matched in bandwidth to that of the hop pulses, this would be a very poor choice. Intuitively, it can be seen that TK should be "matched" to the presence of hop pulses in each channel; i.e., the channel integrator is enabled (integrates) when a pulse is present and is disabled (holds) when a pulse is absent. But the detector has no idea when *the factor N, which represents a correction from a Gaussian assumption to chi-squared statis- tics, is discussed in (3) of Section 1.2.1.2. Low Probability of Intercept Communications the various hits in each channel will occur; thus, the "matched" strategy is totally impractical. There is no recourse, then, but to make TK = TM- Therefore, (1A.2) Now the single-channel wideband radiometer (which occurs if K=1) = has its performance given by: (1A.3) If it is assumed that WSSTM> SS 1 and WT/1,then NWB and NK can both be conveniently taken as unity. Substituting (1A.3) into (1A.2) gives (1A.4) Now, assume for the moment that the (S/No) input to the K channel radiome- ter is exactly (S/No)wb On the basis of equal energy division between the K channels, the available (S/No)k is (1A.5) further, taking dk = dwb (as a bounding worst case assumption), by com- paring (1A.5) with (1A.4), it is readily seen that the available (S/No)k is a factor of 1/VK lower than that required by (1A.4). Clearly, then, if parity is to be achieved between the two detectors, it is nec