“Two of Armstrong’s three key inventions were made while he was at Columbia.”
Edwin Howard Armstrong (1890–1954), Inventor
Columbia Engineering Class of 1913
Faculty 1913–54
Armstrong invented three of the electronic circuits fundamental to modern radio, television, and radar. The first was a new “regenerative” circuit, based on the audion tube, which eventually yielded the first radio amplifier. The second was a complex eight-tube receiver, known as the superheterodyne circuit, that amplified weak signals to a degree previously impossible. This circuit, which Armstrong invented while serving as an officer in the U.S. Army Signal Corps during World War I, remains a basic component of nearly all radio and television receivers today. Most notably, he designed an entirely new system—wide-band frequency modulation (FM)—that offered the highest-fidelity sound yet heard in radio. In World War II he again served in the army, aiding troops in the use of FM radio. Plagued from his early inventing years onwards by legal battles with corporations over the rights to his inventions, Armstrong committed suicide in 1954.
Two of Armstrong’s three key inventions were made while he was at Columbia. The audion tube came into being during his junior year at the School of Engineering; upon graduating in 1913, he filed for a patent and returned to Columbia as an instructor and assistant to Professor Michael I. Pupin, the pioneering electrical engineer. When he returned to Columbia after the war, he accepted no salary and devoted himself full-time to research to work on FM. Armstrong received an honorary degree in 1929. He was posthumously elected by the International Telecommunications Union in Geneva to the roster of electrical greats to stand beside Alexander Graham Bell, Guglielmo Marconi, and Michael Pupin.