Columbia Encyclopedia

Search results

500 results found

microphone

(Encyclopedia)microphone, device for converting sound into electrical energy, used in radio broadcasting, recording, and sound amplifying systems. Its basic component is a diaphragm that responds to the pressure or...

Armstrong, Edwin Howard

(Encyclopedia)Armstrong, Edwin Howard, 1890–1954, American engineer and radio inventor, b. New York City, grad. Columbia (E.E. 1913). He was associated in research with Michael I. Pupin at Columbia and became pro...

FM, abbreviation for frequency modulation

(Encyclopedia)FM: see modulation; radio. ...

AM, abbreviation for amplitude modulation

(Encyclopedia)AM: see modulation; radio. ...

modulation, in communications

(Encyclopedia)CE5 Modulation modulation, in communications, process in which some characteristic of a wave (the carrier wave) is made to vary in accordance with an information-bearing signal wave (the modulatin...

audio frequency

(Encyclopedia)audio frequency: see sound; radio. ...

frequency modulation

(Encyclopedia)frequency modulation: see modulation; radio. ...

amplitude modulation

(Encyclopedia)amplitude modulation: see modulation; radio. ...

Davis, Elmer

(Encyclopedia)Davis, Elmer, 1890–1958, American newspaperman, radio commentator, and author, b. Aurora, Ind. Davis was a Rhodes scholar (1910–13) at Oxford. For 10 years (1914–24) he was on the staff of the N...

galaxy

(Encyclopedia)CE5 Hubble classification of galaxies: Elliptical galaxies (E) are classified according to the degree of flattening of the ellipse. Spiral galaxies (S) and barred spiral galaxies (SB) are classifie...