Patent ID: 8576948

Claim:
An angle modulator using a frequency locked loop circuit, the frequency locked loop comprising a subtractor, a loop filter, a voltage controlled oscillator that has a plurality of operational modes and generates an angle modulated signal by switching the operational mode according to a mode switching signal, and a frequency detection section that detects a frequency of the angle modulated signal, the subtractor subtracting the frequency detected by the frequency detection section from an input signal of the subtractor; the angle modulator comprising: a phase difference detection section that detects a difference of phases between an angle signal input to the angle modulator and the angle modulated signal; a correction control section that inputs the mode switching signal, and that generates a control signal that compensates the difference of phases on the basis of the difference of phases and the input mode switching signal; and a correction section that corrects the phase of the angle modulated signal by adding the control signal to the angle signal, an input signal of the loop filter, or an input signal of the voltage controlled oscillator; wherein the subtractor receives as input a frequency signal corresponding to the angle signal, or a frequency signal corresponding to a signal obtained by adding the control signal to the angle signal.