Edwin Howard Armstrong Biography (1890-1954)

electrical engineer

An extremely innovative inventor, Edwin Armstrong unfortunately spent as muchtime in court fighting lawsuits as he did in the laboratory. Born on December 18, 1890, Armstrong decided he was going to be an inventor by age fourteen.He had read of Guglielmo Marconi and became very interested in wireless radio communication. Before he was twenty he had built his own transmitter and was broadcasting radio signals. He enrolled at Columbia University, studied under Michael Pupin (1858-1935), and received a degree in electrical engineeringin 1913. In 1912 Armstrong created one of his three major inventions, the regenerative circuit. Working with the audion, a vacuum tube invented byLee de Forest to detect radio signals, he discovered that feeding the tube'scurrent back into itself enhanced the sensitivity of the tube greatly. He was able to amplify distant radio signals loudly enough to be heard without theuse of headphones. He also noted that a suitably overloaded audion could beused to transmit radio waves. Armstrong applied for a patent, and promptly wound up in the midst of a four-way lawsuit. De Forest, Irving Langmuir at General Electric, and Alexander Meissner in Germany all claimed priority. Langmuir and Meissner were soon eliminated from the suit, but the complex case withde Forest dragged on for twenty years. De Forest had essentially invented a telephone circuit that had the potential for radio amplification, whereas Armstrong had invented the circuit specifically for radio. The courts initially upheld Armstrong's patent, but de Forest, backed by AT&T, was ableto convince the Supreme Court to overturn the original ruling. Technically knowledgeable scientists continued to credit Armstrong for the discovery and gave him numerous awards. Before Armstrong's invention could be put to wide use, World War I intervened. Armstrong became an officer in the U. S. Signal Corps and was sent to Paris, France, where he made his second important invention. In 1917 he improved Reginald Aubrey Fessenden 's heterodyne technology toamplify weak signals, and created the superheterodyne circuit. Although his original hope of using it to detect enemy aircraft did not materialize, the circuit became the basis for 98 percent of the receivers used in radio and television to make them tunable with the twist of a dial. After the war Armstrongreturned to Columbia and developed the supergenerative circuit in 1920, which became widely used in police, aircraft and amateur radio receivers. He thenaddressed the problem of static that was plaguing radio reception. Fessendenhad invented amplitude modulation (AM) of radio waves in 1906, which made transmission of voice and music possible, but electromagnetic interference caused by lightning storms created bursts of static that broke up the signal. In1933 Armstrong devised a method of modulating the frequency of the wavelengths, rather than the amplitude. Frequency modulation (FM), Armstrong's third major invention, produced extremely clear sound and was immune to electromagnetic interference. It also opened the door for multiplex and stereo broadcasting, as well as microwave relay links. But frequency modulation had a very difficult birth. First, the depressed economy of the 1930s did not encourage major investments in new technology. The Federal Communications Commission (FCC)didn't grant his permit to initiate FM broadcasting until 1940. Then World War II came along and delayed development. Following the war, the major broadcasters did all they could to hamper development, seeing FM's potential as a competitor with their established AM stations and new television technology. The FCC was influenced to arbitrarily change the frequencies allotted to FM andlimit FM signal power. When the major corporations finally got involved withFM, they began using Armstrong's patents. Armstrong filed suit against RCA and its subsidiaries for infringing on his patents. But he could bear no more.On January 31, 1954, demoralized and his health failing, Armstrong jumped tohis death from his apartment in New York City. His widow continued to press21 lawsuits, eventually won every one of them, and received a $10,000,000 settlement.

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