Patent ID: 9748983
Date: 2017-08-29
CPC Classifications: H03F,H04B

Claim:
1. A transmitter comprising: a baseband amplitude value distribution processor that changes a distribution of an amplitude value of a baseband signal based on a control signal that has been input and outputs the baseband signal as an output signal; a digital transmitter that ΔΣ modulates the output signal of the baseband amplitude value distribution processor and transmits the modulated signal; an in-band distortion measurer that measures an in-band distortion amount of the output signal of the baseband amplitude value distribution processor; an amplitude value distribution measurer that calculates an amplitude value distribution of the output signal of the baseband amplitude value distribution processor; a sideband distortion predictor that predicts a sideband distortion amount occurring in the output signal in the digital transmitter from the amplitude value distribution calculated in the amplitude value distribution measurer; and a baseband processing controller that adjusts the control signal to be input to the baseband amplitude value distribution processor based on the in-band distortion amount measured in the in-band distortion measurer and the sideband distortion amount predicted in the sideband distortion predictor and outputs the adjusted control signal, wherein the sideband distortion predictor calculates the sideband distortion amount using a correlation of the amplitude value of the output signal and the sideband distortion amount obtained by measuring changes in the amplitude value of the output signal to be input to the digital transmitter and changes in the sideband distortion amount of the modulated signal to be output from the digital transmitter.