US PATENT SUBCLASS 375 / 298
.~ Quadrature amplitude modulation


Current as of: June, 1999
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375 /   HD   PULSE OR DIGITAL COMMUNICATIONS

295  DF  TRANSMITTERS {6}
298.~ Quadrature amplitude modulation


DEFINITION

Classification: 375/298

Quadrature amplitude modulation:

(under subclass 295) Subject matter in which the transmitted signal can be represented as the superposition of two modulated signals, each being obtained by pulse amplitude modulation of a signal sequence on a sinusoidal carrier, the two signal sequences being generated in synchronization at the same rate, and the two carriers being of the same frequency but 90 degrees apart in phase.

SEE OR SEARCH THIS CLASS, SUBCLASS:

261, for quadrature amplitude modulation system using alternating or pulsating current.

316+, for quadrature amplitude modulation receivers.

SEE OR SEARCH CLASS

370, Multiplex Communications,

206, for multiplex communications using quadrature carriers.

455, Telecommunications, 60, for analog transmission via plural phases of one carrier.