Patent ID: 8315579

Claim:
A semiconductor integrated circuit for communication comprising: a modulation circuit, including a mixer having differential input terminals and differential output terminals, which is used for generating a transmission signal by mixing a baseband signal for transmission and a carrier wave signal; and a calibration circuit coupled to the differential input terminals of the modulation circuit; and a comparator circuit coupled to the differential output terminals of the mixer and the calibration circuit, wherein the comparator circuit detects a potential difference of the differential outputs of the mixer in a state where potentials at both of the differential input terminals of the modulation circuit are controlled to be equal to each other and the mixer is blocked so that the carrier wave signal is not input, and wherein the comparator circuit outputs a detection result into the calibration circuit, and wherein the calibration circuit changes potentials of the differential inputs of the mixer on the basis of the detection result, thereby reducing the potential difference of the differential output terminals.