Reginald Fessenden

Reginald Aubrey Fessenden was a brilliant Canadian-born inventor and electrical engineer who held hundreds of patents in telecommunications, acoustics, and navigation. Realizing that continuous modulated radio waves—rather than spark-gap telegraphic pulses—were needed for sound transmission, he conceived the heterodyne principle and developed high-frequency alternators.

On December 24, 1906, from Brant Rock, Massachusetts, Fessenden transmitted the first verified voice and music broadcast in history, playing "O Holy Night" on his violin to astonished shipboard operators across the Atlantic. He also invented the sonic depth sounder and submarine signaling apparatus.