Who said actress aren’t smart? Here’s a reference to the patent on Google.
Hedy Lamarr (November 9, 1913 – January 19, 2000) was an Austrian/American actress and communications technology innovator. Though known primarily for her great beauty, she also co-invented the first form of spread spectrum, a key to modern wireless communication.
The most celebrated invention of frequency hopping was that of actress Hedy Lamarr and composer George Antheil, who in 1942 received patent number 2,292,387 for their “Secret Communications System”. (Lamarr had learned about the problem at defense meetings she had attended with her husband at the time, Fritz Mandl, an arms manufacturer. ) This version of frequency hopping used a piano-roll to change between 88 frequencies, and was intended to make radio-guided torpedoes harder for enemies to detect or to jam.