More:
"The most celebrated invention of frequency hopping was that of
actress Hedy Lamarr and composer George Antheil, who in 1942 received
U.S. Patent 2,292,387 for their "Secret Communications System". This
early version of frequency hopping used a piano-roll to change among
88 frequencies, and was intended to make radio-guided torpedoes harder
for enemies to detect or to jam. The patent was rediscovered in the
1950s during patent searches when private companies independently
developed Code Division Multiple Access, a civilian form of
spread-spectrum."
http://en.wikipedia.org/wiki/Frequency_hopping
--