Edwin Howard Armstrong

(1890—1954) American electrical engineer

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Lee De Forest (1873—1961) American physicist and electrical engineer


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US electrical engineer, who invented the superheterodyne radio receiver and the FM radio.

The son of a publisher, he was educated at Columbia University, New York. He joined the faculty shortly after graduating in 1913 and became professor of electrical engineering in 1934, a post he held until his death. A highly inventive engineer with forty-two patents to his name, he was responsible for two very important innovations that have had a profound impact on the development of radio. The first arose from his work with the US Signals during World War I and involved attempts to detect distant aircraft by the electromagnetic signals they produced. To tune in to such high frequencies Armstrong designed a ‘superheterodyne circuit’ that allowed the complicated task of tuning to be performed by the simple turning of a knob. This device enabled radio to become available for everyone. Although he received half a million dollars for his invention from Westinghouse, it also involved him in a prolonged, expensive, and bitter legal battle with Lee De Forest, the inventor of the triode valve.

Armstrong's second major invention proved no less contentious. It arose from his plan of reducing the static that ruined so much of early broadcasting. Realizing that much of this static arose as a result of amplitude modulation, he devised a means of removing it completely by using frequency modulation (FM). Surprisingly, RCA and other broadcasting companies objected to the proposal in the 1930s and further delays were caused by the outbreak of World War II. Depressed by obstacles put in his way by the US government and the broadcasting companies and impoverished by the constant litigation that accompanied his work, Armstrong committed suicide in 1954.

Subjects: Contemporary History (Post 1945).

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