tion in New York, discussed his radio receiver invention with ITT engineer and patent attorney Paul Adams. Marchand had developed a converter for demodulating a received FM sig- nal of known frequency wobbulation by mixing it with a time-aligned, het- erodyned replica of the wobbulated signal to produce a signal of constant intermediate frequency (IF) which could then be narrow-band filtered. The receiver's anti-multipath attributes designed by Marchand and additional anti-interference features suggested by Adams appear in a 1947 patent [38]. Later during World War II, after studying Wiener's "Yellow Peril," Marchand was able to dub his converter a bandpass correlator. However, Marchand was neither the first nor the last to propose the band- pass correlator, a similar device being contained in Purington's 1930 patent application [39]. At M.I.T. in 1947, Prof. Yuk Wing Lee commenced research into the impli- cations of Wiener's theories and the new directions they inspired for engi- neering science. Soon thereafter, Lee was joined by Jerome Wiesner and Thomas Cheatham, and their collective efforts led to the development of the first high-performance electronic correlators. In August 1949, they applied for a patent [40] and in October they reported applications of correlation techniques to detection problems [41]. Continuing this work, Henry Singleton proceeded to innovate an all-digital correlator [42]. 2.1.4 Protected Communications It has been found [6], [43, p. 1] that secrecy, jamming, and anti-jamming had each begun to stir attention as early as 1901. (Note: For further details see [44, pp. 38-39], where also a recommendation is mentioned that "the hom- ing-pigeon service should be discontinued as soon as some system of wire- less telegraphy is adopted.") The first two of these three differing adversary-recourses were astutely exercised together in reporting, by "wire- less," the America's Cup yacht race of that year. They were invoked by a thereby countermeasures-pioneering engineer who was competing against 