Digital modulator, communication device, and digital modulator control method

A communication device comprising:

• a digital modulator;
• and
• an optical module configured to perform signal processing on the basis of an output signal of the digital modulator,
• wherein the digital modulator comprises:
• a polar converter configured to generate a phase signal and an amplitude signal from a baseband signal;
• an RF phase signal generator configured to generate an RF phase signal on the basis of the phase signal;
• a rectangulating unit configured to generate a rectangular RF phase signal by converting the RF phase signal into a rectangular shape;
• a time interleaver configured to time interleave the amplitude signal, and output a first interleaved signal and a second time interleaved signal;
• a ΔΣ modulator configured to ΔΣ modulate the first interleaved signal and the second time interleaved signal on the basis of the rectangular RF phase signal, and output a first ΔΣ modulated signal and a second ΔΣ modulated signal;
• and
• a selector configured to receive as input the first ΔΣ modulated signal and the second ΔΣ modulated signal, and select and output one of the first ΔΣ modulated signal and the second ΔΣ modulated signal on the basis of the rectangular RF phase signal.

A digital modulator control method comprising:

• generating a phase signal and an amplitude signal from a baseband signal;
• generating an RF phase signal on the basis of the phase signal;
• generating a rectangular RF phase signal by converting the RF phase signal into a rectangular shape;
• time interleaving the amplitude signal, and outputting a first interleaved signal and a second time interleaved signal;
• ΔΣ modulating the first interleaved signal and the second time interleaved signal on the basis of the rectangular RF phase signal, and outputting a first ΔΣ modulated signal and a second ΔΣ modulated signal;
• and
• inputting the first ΔΣ modulated signal and the second ΔΣ modulated signal, and selecting and outputting one of the first ΔΣ modulated signal and the second ΔΣ modulated signal on the basis of the rectangular RF phase signal.