Patent ID: 7772931
Filing Date: 2010-08-10
Classification: H03H,H03L

Abstract:
1. An oscillator comprising: a reference signal generator that generates a reference signal having a reference frequency; a phase comparator that outputs a voltage in accordance with a phase difference between the reference signal and a feedback signal; a loop filter that receives the voltage output from the phase comparator, and gain-adjusts the voltage output from the phase comparator by means of an external control signal; a voltage controlled oscillator that oscillates an output signal at a frequency in accordance with an adjusted signal having been gain-adjusted by the loop filter; a frequency divider that feeds back a frequency-divided signal resulting from frequency-dividing the output signal, to the phase comparator as the feedback signal; and a controller that outputs the external control signal to control the loop filter according to a sensitivity of the voltage controlled oscillator or a division ratio of the frequency divider by means of the external control signal, wherein the controller controls a gain of the loop filter so that a total gain of the oscillator becomes a target value according to the frequency set to the output signal.