Patent ID: 8207765

Claim:
A signal generating apparatus that generates an output signal having a designated phase, comprising: a phase difference detecting section that outputs a control signal corresponding to a phase difference between a reference signal having a prescribed period and the output signal; a loop filter that eliminates a high-band component of the control signal; an oscillating section that generates a periodic signal having a frequency corresponding to the control signal from which the high-band component has been eliminated by the loop filter; and a phase shifting section that outputs the output signal to have a phase that is shifted from the phase of the periodic signal by a designated phase amount, wherein the phase shifting section includes: an I-side signal output section that outputs an I-component signal corresponding to a cosine value of the designated phase; a Q-side signal output section that outputs a Q-component signal corresponding to a sine value of the designated phase; and a quadrature modulator that quadrature modulates the periodic signal with the I-component signal and the Q-component signal, the signal generating apparatus further comprises: a phase input section that receives a designated phase shift and supplies the phase shifting section with a component, included in the designated phase, having a frequency higher than a cutoff frequency of the loop filter; a shifting signal output section that outputs a phase signal according to a phase supplied thereto; and an adding section that adds the phase signal to the control signal output by the phase difference detecting section, and supplies the resulting signal to the loop filter, wherein the phase input section supplies the shifting signal output section with a component, included in the designated phase, having a frequency less than or equal to the cutoff frequency of the loop filter.