Patent ID: 8798191
Filing Date: 2014-08-05
Classification: H03F,H04B

Abstract:
1. A transmission apparatus comprising: an angle modulation section that generates an angle modulated signal in a radio frequency domain using an angle signal of an input signal; an amplitude modulator that generates a modulated signal by amplifying power of the angle modulated signal according to an amplitude signal of the input signal; a first generation section that generates a digital amplitude signal by performing analog to digital conversion on the amplitude signal; a second generation section that generates a digital angle modulated signal corresponding to a signal obtained by performing analog to digital conversion on the angle modulated signal; a multiplier that generates, in a pseudo manner, a digital modulated signal corresponding to a signal that is obtained by performing analog to digital conversion on the modulated signal, by multiplying the digital amplitude signal by the digital angle modulated signal; a distortion calculation section that calculates distortion of the digital modulated signal; an adjustment section that adjusts delay time until the amplitude signal is input to the amplitude modulator, or delay time until the angle modulated signal is input to the amplitude modulator; and a control section that controls the delay time based on the distortion, wherein: the second generation section comprises: an analog to digital converter that generates a digital angle signal by performing analog to digital conversion on the angle signal; and a digital angle modulation section that generates the digital angle modulated signal in a baseband domain based on the digital angle signal, wherein: the angle signal is a phase signal; the digital angle signal is a digital phase signal that is obtained by performing analog to digital conversion on the phase signal; the angle modulation section is a phase modulator; the digital angle modulation section comprises a complex number calculation section that generates a digital real number signal and a digital imaginary number signal that are obtained by performing analog to digital conversion on a real number component and an imaginary number component of the phase signal using the digital phase signal, as the digital angle modulated signals; and the multiplier comprises: a first multiplier that generates a real number component of the digital modulated signal by multiplying the digital amplitude signal by the digital real number signal; and a second multiplier that generates an imaginary number component of the digital modulated signal by multiplying the digital amplitude signal by the digital imaginary number signal; wherein: the distortion calculation section calculates the distortion using the real number component and the imaginary number component of the digital modulated signal.