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digital-to-analog conversion
(Encyclopedia)digital-to-analog or D/A conversion, the process of changing discrete digital data into a continuously varying signal in relation to a standard or reference. There are two types of converters: electro...DeCarava, Roy
(Encyclopedia)DeCarava, Roy, 1919–2009, American photographer, b. Harlem, New York City, as Roy Rudolph DeCarava; he studied (1944–45) under Charles White at theGeorge Washington Carver Art School. He intended ...Paul, Les
(Encyclopedia)Paul, Les, 1915–2009, American guitarist and inventor, b. Waukesha, Wis., as Lester William Polsfuss (later Polfuss). He began playing country music a...Kelvin, William Thomson, 1st Baron
(Encyclopedia)Kelvin, William Thomson, 1st Baron, 1824–1907, British mathematician and physicist, b. Belfast. He was professor of natural philosophy at the Univ. of Glasgow (1846–99). He is known especially for...learning disabilities
(Encyclopedia)learning disabilities, in education, any of various disorders involved in understanding or using spoken or written language, including difficulties in listening, thinking, talking, reading, writing, s...Bell, Alexander Graham
(Encyclopedia)Bell, Alexander Graham, 1847–1922, American scientist, inventor of the telephone, b. Edinburgh, Scotland, educated at the Univ. of Edinburgh and University College, London; son of Alexander Melville...pulsar
(Encyclopedia)pulsar, in astronomy, a neutron star that emits brief, sharp pulses of energy instead of the steady radiation associated with other natural sources. The study of pulsars began when Antony Hewish and h...Edison, Thomas Alva
(Encyclopedia)Edison, Thomas Alva, 1847–1931, American inventor, b. Milan, Ohio. A genius in the practical application of scientific principles, Edison was one of the greatest and most productive inventors of his...Douglass, Frederick
(Encyclopedia)Douglass, Frederick dŭgˈləs [key], c.1818–1895, American abolitionist, b. near Easton, Md. as Frederick Augustus Washington Bailey. The son of a black slave, Harriet Bailey, and a white father, m...David, Jacques-Louis
(Encyclopedia)David, Jacques-Louis zhäk-lwēˈ dävēdˈ [key], 1748–1825, French painter. David was the virtual art dictator of France for a generation. Extending beyond painting, his influence determined the c...Browse by Subject
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