 the very practical problem of building frequency synthesizers able to produce 2 X 107 frequencies of the required spacing with the necessary accuracy and stability. Nevertheless, the example serves to show that FH/PN Interception Detectors is not necessarily superior to pure FH from a sophisticated detector point of view. As a final point, it should be stated at this juncture that, although the use of PN spreading appears, under appropriate conditions, to doom the PB-FBC to a position of virtual uselessness, the PB-FBC actually attains this distinc- tion on its own when the effects of imperfect frequency synchronization are included in its performance (as discussed in the next section). Thus, the addi- tion of PN spreading will only act to "add icing to the cake." The real value of the PN coding, if it is to have some effective purpose, is to combat jam- ming of the receiver SO that the communicator does not have to increase his transmitter power to overcome the jamming to the same limit as that required when no PN modulation is employed. 1.2.2 Non-Idealistic Detector Performance 1.2.2.1 The Problem of Time Synchronization The detector performance discussed to this point has been computed on the basis of ideal conditions in that the interceptor has been assumed to have information necessary for perfect time and frequency synchronization. In the case of the former, this is equivalent to saying that the interceptor has exact knowledge of both the time at which a single message transmission origi- nates and the epochs of the individual hop pulses. In this section, the penalty paid (in increased SIN required) by the inter- ceptor for total lock of time synchronization information is determined. For this more practical or realistic condition, it will be necessary to consider adjunct capabilities to the detectors of Section 1.2.1. Only the wideband energy detector and the FBC will be investigated as they represent the most viable types of detectors useful to the interceptor. The only continuing assumption will be that