Patent ID: 7994867

Claim:
An oscillator control apparatus comprising: a digitally-controlled oscillator which outputs an oscillation signal having an oscillation frequency in response to an oscillator adjusting signal; a counter which counts the oscillation signal and outputs a count in response to a reference signal in synchronism with the oscillation signal; a time-to-digital converter which calculates a phase difference between the oscillation signal and the reference signal; an adder which adds the count and the phase difference and outputs the added value as first phase information; a corrector which corrects the first phase information in response to a phase control signal for setting an oscillation frequency of the digitally-controlled oscillator when a time difference between a rising-up timing of the oscillation signal and a rising-up timing of the reference signal is less than a predetermined time, and outputs second phase information; and a filter for smoothing a difference between the phase control signal and the second phase information, to output the oscillator adjusting signal.