chniques behavior and performance of a similar estimation technique for fine fre- quency synchronization [2], i.e., relative frequency errors between trans- mitter and receiver hop generators of less than one-half the frequency spacing of the MFSK tones. Here, in calculating the degrading effect on overall system error probability performance because of the residual fre- quency error produced by the fine frequency estimation technique, the additional degradation due to imperfect fine time synchronization is taken into account. Finally, when both fine time and fine frequency esti- mators are assumed to augment each other, we are able to obtain the over- all performance degradation due to the combination of both residual synchronization errors. The interference environment in which the time and frequency estimators are assumed to operate is that of the noise (partial- or full-band) jammer. Thus, the overall performance degradation referred to above will be a func- tion of the partial-band fraction, the noise jamming level, and the number of hops used in forming the FH timing and frequency estimates. The per- formance of these estimators in other narrowband interference environ- ments such as partial-band multitone jamming can be obtained in a straightforward manner using the analytical approach in Chapter 2, Part 2. 3.1 FH ACQUISITION TECHNIQUES Coarse frequency synchronization is the process by which the local gener- ated hop sequence is aligned with the received hop sequence to within a frac- tion of a hop interval. This acquisition process is normally thought of as being accomplished in two steps. First, the degree of alignment is determined, typ- ically, by obtaining a measure of correlation (active or passive) between the two hop sequences. Second, the correlation measure is processed by a suit- able detector and decision/search algorithm to decide whether or not to con- tinue the search. If, at any point, the search terminates, then coarse frequency acquisition is assumed to have occurred. 3.1.1 Serial Search