Edwin H. Armstrong, in full Edwin Howard Armstrong, (born December 18, 1890, New York, New York, U.S.—died January 31/February 1, 1954, New York City), American inventor who laid the muse for a lot of recent radio and digital circuitry, together with the regenerative and superheterodyne circuits and the frequency modulation (FM) system.
Armstrong was from a genteel, devoutly Presbyterian household of Manhattan. His father was a writer and his mom a former schoolteacher. Armstrong was a shy boy from childhood in engines, railway trains, and all mechanical contraptions.
At age 14, fired by studying of the exploits of Guglielmo Marconi in sending the primary wi-fi message throughout the Atlantic Ocean, Armstrong determined to turn into an inventor. He constructed a maze of wi-fi equipment in his household’s attic and started the solitary, secretive work that absorbed his life. Except for a ardour for tennis and, later, for quick motor automobiles, he developed no different vital pursuits. Wireless was then within the stage of crude spark-gap transmitters and iron-filing receivers, producing faint Morse-code indicators, barely audible by means of tight earphones. Armstrong joined within the hunt for improved devices. On graduating from highschool, he commuted to Columbia University’s School of Engineering.
In his junior yr at Columbia, Armstrong made his first, most seminal invention. Among the units investigated for higher wi-fi reception was the then little understood, largely unused Audion, or three-element vacuum tube, invented in 1906 by Lee De Forest, a pioneer within the improvement of wi-fi telegraphy and tv. Armstrong made exhaustive measurements to learn how the tube labored and devised a circuit, known as the regenerative, or suggestions, circuit, that immediately, within the autumn of 1912, introduced in indicators with a thousandfold amplification, loud sufficient to be heard throughout a room. At its highest amplification, he additionally found, the tube’s circuit shifted from being a receiver to being an oscillator, or main generator, of wi-fi waves. As a radiowave generator, this circuit remains to be on the coronary heart of all radio-television broadcasting.
Armstrong’s precedence was later challenged by De Forest in a monumental collection of company patent fits, extending greater than 14 years, argued twice earlier than the U.S. Supreme Court, and eventually ending—in a judicial misunderstanding of the character of the invention—in favour of De Forest. But the scientific group by no means accepted this verdict. The Institute of Radio Engineers refused to revoke an earlier gold-medal award to Armstrong for the invention of the suggestions circuit. Later he acquired the Franklin Medal, highest of the United States’ scientific honours, reaffirming his invention of the regenerative circuit.
This youthful invention that opened the age of electronics had profound results on Armstrong’s life. It led him, after a stint as an teacher at Columbia University, into the U.S. Army Signal Corps laboratories in World War I in Paris, the place he invented the superheterodyne circuit, a extremely selective technique of receiving, changing, and enormously amplifying very weak, high-frequency electromagnetic waves, which immediately underlies 98 p.c of all radio, radar, and tv reception over the airways. It introduced him into early affiliation with the person destined to guide the postwar Radio Corporation of America (RCA), David Sarnoff, whose younger secretary Armstrong later married. Armstrong himself returned after the battle to Columbia University to turn into assistant to Michael Pupin, the notable physicist and inventor and his revered instructor. In this era he offered patent rights on his circuits to the most important firms, together with RCA, for big sums in money and inventory. Suddenly, within the radio growth of the Twenties, he discovered himself a millionaire. But he continued to show at Columbia, financing his personal analysis, working together with Pupin, whose professorship he inherited, on the long-unsolved downside of eliminating static from radio.
In 1933 Armstrong secured 4 patents on superior circuits that have been to unravel this final fundamental downside. They revealed a wholly new radio system, from transmitter to receiver. Instead of various the amplitude, or energy, of radio waves to hold voice or music, as in all radio earlier than then, the brand new system different, or modulated, the waves’ frequency (variety of waves per second) over a large band of frequencies. This created a provider wave that pure static—an amplitude phenomenon created by electrical storms—couldn't break into. As a outcome, FM’s broad frequency vary made attainable the primary clear, sensible methodology of high-fidelity broadcasting.
Because the brand new system required a fundamental change in transmitters and receivers, it was not embraced with any alacrity by the established radio trade. Armstrong needed to construct the primary full-scale FM station himself in 1939 at a value of greater than $300,000 to show its price. He then needed to develop and promote the system, maintain it by means of World War II (whereas he once more turned to army analysis), and battle off postwar regulatory makes an attempt to hobble FM’s progress. When FM slowly established itself, Armstrong once more discovered himself entrapped in one other interminable patent swimsuit to retain his invention. Ill and growing old in 1954, with most of his wealth gone within the battle for FM, he took his personal life.
The years have introduced growing recognition of Armstrong’s place in science and invention. FM is now the popular system in radio, the required sound channel in all tv, and the dominant medium in cell radio, microwave relay, and space-satellite communications. Posthumously, Armstrong was elected to the pantheon {of electrical} greats by the International Telecommunications Union, to affix such figures as André-Marie Ampère, Alexander Graham Bell, Michael Faraday, and Guglielmo Marconi.