DIGITAL MODULATOR, COMMUNICATION DEVICE, CONTROL METHOD FOR DIGITAL MODULATOR, AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide a digital modulator capable of improving an SN ratio in a communication device having a ΔΣ modulator.;SOLUTION: A digital modulator includes a polar converter that generates a phase signal and an amplitude signal from a quadrature signal that is a baseband signal, an oscillator that generates an oscillation signal serving as a reference of a phase and an oscillation frequency, an RF phase signal generator that generates a first rectangular wave having a first oscillation frequency and a first phase difference whose phase difference from the oscillation signal is equal to the phase indicated by the phase signal and a second rectangular wave having a second phase difference twice that of the first oscillation frequency and a second oscillation frequency twice the first oscillation frequency on the basis of the phase signal and the oscillation signal, a ΔΣ modulator that ΔΣ modulates the amplitude signal by using the second rectangular wave as a clock signal, and a synthesizer that calculates the product of the output signal of the ΔΣ modulator and the first rectangular wave.;SELECTED DRAWING: Figure 6;COPYRIGHT: (C)2019,JPO&INPIT