nceived by Neal Zierler and Bill Davenport, consisted of either transmitting the SS code in its original form (MARK), or transmit- ting it with every other pulse from the SS code generator inverted (SPACE) (see Figure 2.23). Perhaps it was a case of serendipity that several years earlier Fano had suggested communication-through-multipath as an Sc.D. thesis tiopic to Bob Price. In any event, after a particularly frustrating day of field tests in which they encountered highly variable F9C performance, Price and Green got together in their Asbury Park boarding house to discuss multipath problems. Price already knew the optimal answers to some questions that were to come up that evening. Since receiving his doctorate and having been rehired by Davenport after trying his hand at radio astronomy in Australia, he had been polishing his dissertation with "lapidary zeal" (Green's witticism). Price had, in fact, statistically synthesized a signal processing technique for minimum- error-probability reception of signals sent over a channel disturbed by time- varying multipath as well as noise [150]. Green separately had been trying to determine how to weight the out- puts of a time-staggered bank of correlators in order to improve F9C per- formance, and, acting on Jack Wozencraft's suggestion, had decided to choose weights to maximize the resultant capability of the F9C was suffi- cient to guarantee that the outputs of different correlators in the bank rep- resented signals arriving via different paths. Thus, the problem was one of efficiently recombining these signals. It took little time for Price and Green to realize that the results of their two approaches were nearly iden- tical, and from that evening onward, the "Rake" (coined by Green) estimator-correlator became part of their plans for the F9C. Price took charge of building the Rake prototype, with the assistance of John Craig and Robert Lerner. Related to Wiesner and Lee's work on system function measurements using cross correlation [151], Brennan's work on signal-c