Patent ID: 8406283

Claim:
A modulation apparatus that quadrature modulates a periodic signal, comprising: an I-side signal output section that outputs an I-component signal; a Q-side signal output section that outputs a Q-component signal; a quadrature modulator that quadrature modulates the periodic signal with the I-component signal and the Q-component signal; an I-side correcting section that corrects the I-component signal according to an error of the quadrature modulator; a Q-side correcting section that corrects the Q-component signal according to the error of the quadrature modulator; and a calibration section that measures the error of the quadrature modulator and sets correction amounts corresponding to the measured error in the I-side correcting section and the Q-side correcting section, the calibration section including: a control section that causes the I-side signal output section to output a predetermined I-component signal, causes the Q-side signal output section to output a predetermined Q-component signal, and causes the quadrature modulator to perform quadrature modulation; a measuring section that measures power of the output signal from the quadrature modulator; a calculating section that calculates a quadrature error, a gain error, and an origin offset of the quadrature modulator based on the measurement result from the measuring section; and a setting section that sets correction amounts corresponding to the calculated errors in the I-side correcting section and the Q-side correcting section.