Patent ID: 8742865

Claim:
A polar modulation transmission circuit comprising: an extraction section that extracts an amplitude signal and a phase signal from a modulated signal to output the amplitude signal and the phase signal; an amplitude control section that outputs a voltage corresponding to the amplitude signal; a phase compensation section that performs phase compensation by operating on the phase signal with a phase compensation amount corresponding to the amplitude signal; a phase modulation section that performs phase modulation of a high-frequency signal using the phase signal to which the phase compensation is performed, and generates a phase modulation signal; an amplifying section that sets the voltage output from the amplitude control section as a power supply voltage, amplifies the phase modulation signal output from the phase modulation section, and outputs the amplified phase modulation signal; and conversion section that performs a fast Fourier transform of the output signal of the amplifying section to output a frequency spectrum signal to the phase compensation section, wherein the phase compensation section acquires power levels of a low-frequency band and a high-frequency band, which have an identical mistuned frequency, in each delay amount from a value of the frequency spectrum signal in different delay amounts, calculates a relative level difference between the power levels of the low-frequency band and the high-frequency band in each delay amount determines a compensation characteristic in order to compensate an amplitude-phase characteristic of the amplifying section based on a relationship between the relative level difference and the delay amount, and determines the phase compensation amount corresponding to the amplitude signal in the determined compensation characteristic.