Columbia Encyclopedia

(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...

(Encyclopedia) modulation, in music, shift in the key center of a composition. For its accomplishment use is made of the fact that each chord figures in the harmonic relationships of several keys. In modulating from...

(Encyclopedia) phase modulation: see modulation. ...

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

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

(Encyclopedia) pulse code modulation: see modulation. ...

(Encyclopedia) pulse position modulation: see modulation. ...

(Encyclopedia) communications satellite artificial satellite that functions as part of a global radio-communications network. Echo 1, the first communications satellite, launched in 1960, was an instrumented inflat...

(Encyclopedia) communications industry, broadly defined, the business of conveying information. Although communication by means of symbols and gestures dates to the beginning of human history, the term generally ref...

(Encyclopedia) Communications Satellite Corporation (Comsat), organization incorporated (1962) by an act of Congress to establish a commercial system of international communications using artificial satellites. Alth...