Patent ID: 7312665

Claim:
An oscillation control apparatus equipped with a PLL, comprising: a voltage controlled oscillator that has a variable resonator that changes f/v sensitivity according to a control signal; a frequency divider that performs a frequency division of a frequency of an entered output signal of said voltage controlled oscillator; a phase comparator that performs phase comparison between an entered output signal of said frequency divider and a entered reference signal; and a low-pass filter receiving an output signal of said phase comparator and outputs a control voltage to said voltage controlled oscillator, wherein said oscillation control apparatus has a variable resonator control signal generation section that has an output signal of said low-pass filter as input and detects f/v sensitivity of said voltage controlled oscillator, and generates a control signal for controlling said variable resonator based on detected f/v sensitivity, said variable resonator control signal generation section generating a control signal that increases a resonance frequency change width of said variable resonator and raises f/v sensitivity so that f/v sensitivity becomes a reference value when f/v sensitivity of said voltage controlled oscillator varies in a downward direction, and generates a control signal that decreases a resonance frequency change width of said variable resonator and lowers f/v sensitivity so that f/v sensitivity becomes a reference value when f/v sensitivity of said voltage controlled oscillator varies in an upward direction.