DIGITAL MODULATION METHOD, DIGITAL MODULATION CIRCUIT, DIGITAL DEMODULATION METHOD, AND DIGITAL TRANSMISSION SYSTEM

摘要

Provided is a digital modulation method capable of narrowing a base band width while increasing the number of transmission bits per symbol. The digital modulation method deviates the phase of a carrier signal continuously thereby to transmit digital data, and limits the maximum of the phase to be deviated, when digital data of 2 bits or more is transmitted by one phase deviation. A digital modulation circuit includes a base band signal generation circuit (11) for generating a base band signal, of which the maximum of the phase to be deviated is limited, in a manner to meet the digital data of 2 bits or more to be transmitted by one phase deviation, and an orthogonal modulator (12) for modulating the generated base band signal orthogonally.