er information on these early efforts has not been uncovered. In neutral Switzerland, Brown, Boveri, and Company developed, starting in the late 1950s, an SS guidance system (see Figure 2.28). This was no doubt stimulated by Gustav Guanella, the pioneering inventor of noise-modulated radar [13] and of encryption schemes which the NDRC had sought to The Historical Origins of Spread-Spectrum Communications decipher during World War II. He quickly appreciated, and may well have seen, the true significance of the Rake concept upon its publication. Now, an intriguing question is, "When did the Soviet bloc become privy to the SS concept and realize its potential?" In the mid-1950s some members of a high-level U.S. task force were con- vinced that the Russians knew about SS techniques and in fact might also be using them. For example, Eugene Fubini personally searched the U.S. Patent Office open files to see what a foreign country might be able to learn there of this new art; nomenclature was a problem and he had to look under "pulse communications" as well as many other patent classifications. (This difficulty was eased recently when the Patent Office created a special sub- class 375-1 entitled Spread Spectrum.) Also curious about this issue, Paul Green determined to try to find out for himself the status of Russian knowl- edge about NOMAC techniques. After studying the language, he examined the Russian technical literature, surveying their work in information theory and attempting to uncover clues that might lie there to noise modulation concepts. Green came to believe that there was no plausible reason to sus- pect that the Soviets were then developing spread-sectrum systems, partly because of lack of technology and possibly because there was no perceived need for AJ communications capability. Later Paul Green visited the Soviet Union and gave a talk in Russian on the use of Rake to measure properties of the ionosphere, which seemingly was accepted at face value. Because of this contact and his literature scrutiny, i