n, it is possible to calculate the location of the largest spec- tral value without having to calculate the spectrum itself; this is exactly what needs to be accomplished if an FH follower is to be realized. Now the application of the above property to FH following requires that (1) only a finite Th-second time segment be considered and, (2) an answer to be obtained after only a reasonable number of iterations. As a result, some compromise must be allowed in terms of the accuracy of the estimate. Further, even with a Th-second segment of signal-plus-noise to begin with, each successive iteration theoretically doubles the storage or memory required to hold the result; i.e., after n iterations, Rn (t) is generally non- zero over a t range of 2n+11Th Thus, in order to keep the storage needed at a reasonable size, truncation of the iterated function must be allowed SO that Tmax becomes manageable. This will further reduce the accuracy of the result. Nevertheless, for a desired frequency resolution or accuracy, Performance and Strategies Assessment there exists a procedure which will calculate an estimate of f max, namely, f max' after only no iterations. The FH following receiver therefore becomes one which subdivides the received signal-plus-noise into contiguous Th-second periods and applies the autocorrelation iterative estimator to each segment. The successive fre- quency estimates are then taken as being representative of the nearest true hop frequency, and the FH pattern (including the MFSK data) used by the communicator may be reconstructed with occasional errors that depend upon SIN and the finite processing limitations previously summarized. Implementation of an autocorrelation iterating receiver for large SS bandwidths (on the order of GHz) is currently nearly as unrealistic as the full-band spectrum analyzer. To be sure, the total band would have to be sub- divided and individual processors applied to each sub-band. Frequency esti- mates for each sub-band would be obtained along with the normalization fact