Polar modulation transmission circuit and polar modulation transmission method

摘要

Disclosed is a polar modulation transmission circuit wherein distortion components resulting from variations between individual amplifiers are compensated for with few man-hours, and deterioration in signal quality is effectively suppressed. A frequency converter (180) converts the frequency of an output signal of a high frequency power amplifier (170) and outputs a frequency domain signal, and a phase compensation unit (150) measures the power level, for each delay amount, at a low frequency band and high frequency band wherein the detuning frequency from the frequency domain signal is the same, calculates the “unlevel amount” (relative level difference) between the power level of the low frequency band and power level of the high frequency band for each delay amount, and determines the compensation characteristics on the basis of the relationship of the unlevel amount (relative level difference) to the delay amount. Then, the phase compensation unit (150) compensates for the phase signal by adding to the phase signal the phase compensation amount, in the determined compensation characteristics, that corresponds to the amplitude signal.

主权项

1. 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.