Edwin Howard Armstrong (December 18, 1890 – January 31, 1954) was an American electrical engineer and inventor. He has been called "the most prolific and influential inventor in radio history". He invented the regenerative circuit while he was an undergraduate and patented it in 1914, followed by the super-regenerative circuit in 1922, and the superheterodyne receiver in 1918. Armstrong was also the inventor of modern frequency modulation (FM) radio transmission.